diff --git a/analysis_options.yaml b/analysis_options.yaml
index b991a218..11e7dd0f 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -17,6 +17,7 @@ linter:
     prefer_const_constructors: true
     prefer_single_quotes: true
     unawaited_futures: true
+    discarded_futures: true
     avoid_dynamic_calls: true
     cast_nullable_to_non_nullable: true
     null_check_on_nullable_type_parameter: true
diff --git a/assets/languages/strings_de.arb b/assets/languages/strings_de.arb
index e3f21595..54b0cd9e 100644
--- a/assets/languages/strings_de.arb
+++ b/assets/languages/strings_de.arb
@@ -33,8 +33,8 @@
   "buyPaymentConfirmFailedAktionariat": "Es gibt ein technisches Problem. Bitte überprüfen Sie Ihr E-Mail-Postfach, möglicherweise fehlt noch eine Bestätigung Ihrer Blockchain-Adresse. Andernfalls versuchen Sie es später erneut. Falls der Fehler weiterhin besteht, kontaktieren Sie unseren Support.",
   "buyPaymentInformation": "Zahlungsinformationen",
   "buyPaymentInformationDescription": "Bitte überweisen Sie den Kaufbetrag mit diesen Angaben über Ihre Bankanwendung. Der Verwendungszweck ist wichtig!",
-  "buyRealUnit": "RealUnit kaufen",
   "buyRealu": "RealUnit Token kaufen",
+  "buyRealUnit": "RealUnit kaufen",
   "cancel": "Abbrechen",
   "changeAddress": "Adresse ändern",
   "changeInReview": "Änderung in Prüfung",
@@ -53,11 +53,11 @@
   "connectBitboxContent": "Bitte verbinden Sie Ihre BitBox mit Ihrem Smartphone.",
   "connectBitboxContentIos": "Bitte verbinden Sie Ihre BitBox mit Ihrem Smartphone und aktivieren Sie zusätzlich Bluetooth.",
   "connectBitboxFailed": "Es ist ein Fehler aufgetreten. Bitte versuchen Sie es erneut.",
-  "connectBitboxSignInHint": "Nach der Code-Überprüfung wird die BitBox um eine zusätzliche Bestätigung zur Anmeldung gebeten.",
   "connectBitboxSignatureCapturing": "Bitte bestätigen Sie die Anmeldeanfrage auf Ihrem BitBox-Gerät. Diese Signatur wird einmalig erfasst, damit künftige Käufe Ihre BitBox nicht erneut benötigen.",
   "connectBitboxSignatureCapturingTitle": "Anmeldung bestätigen",
   "connectBitboxSignatureFailed": "Ihre Anmeldesignatur konnte nicht erfasst werden. Sie können es erneut versuchen oder trotzdem fortfahren – Ihre BitBox wird dann möglicherweise für Ihren ersten Kauf erneut benötigt.",
   "connectBitboxSignatureFailedTitle": "Anmeldung nicht abgeschlossen",
+  "connectBitboxSignInHint": "Nach der Code-Überprüfung wird die BitBox um eine zusätzliche Bestätigung zur Anmeldung gebeten.",
   "connectBitboxTitle": "BitBox verbinden",
   "connected": "Verbunden",
   "connectedBitboxContent": "Bitte bestätigen Sie und folgen nun den letzten Anweisungen auf Ihrer BitBox.",
@@ -197,8 +197,8 @@
   "proofDocument": "Nachweis-Dokument",
   "purposeOfPayment": "Verwendungszweck",
   "qrCode": "QR-Code",
-  "realunitStockToken": "RealUnit Aktientoken",
   "realunitStockprice": "RealUnit Aktienkurs",
+  "realunitStockToken": "RealUnit Aktientoken",
   "realunitWallet": "RealUnit Wallet",
   "realunitWalletLogout": "Aus REALU Wallet abmelden",
   "realunitWalletLogoutCheck": "Ich habe meine Wiederherstellungsphrase gesichert.",
@@ -246,18 +246,18 @@
   "sellBitboxCheckingEth": "Wallet-Guthaben wird geprüft",
   "sellBitboxDepositDescription": "Bestätigen Sie auf der BitBox, um ZCHF an die DFX-Einzahlungsadresse zu überweisen.",
   "sellBitboxDepositFrom": "Sie senden",
+  "sellBitboxDepositing": "ZCHF wird gesendet. Bestätigen Sie auf der Bitbox",
   "sellBitboxDepositRetryDescription": "Der Tausch wurde abgeschlossen, aber die ZCHF-Einzahlung konnte nicht gesendet werden. Ihre Mittel sind sicher. Tippen Sie auf Wiederholen.",
   "sellBitboxDepositRetryTitle": "Einzahlung fehlgeschlagen",
   "sellBitboxDepositTitle": "ZCHF an DFX senden",
   "sellBitboxDepositTo": "DFX-Einzahlung",
-  "sellBitboxDepositing": "ZCHF wird gesendet. Bestätigen Sie auf der Bitbox",
   "sellBitboxEthReady": "Wallet bereit",
   "sellBitboxEthReadyDescription": "Ihr Wallet hat genug ETH, um mit dem Verkauf fortzufahren.",
   "sellBitboxSwapDescription": "Bestätigen Sie auf Ihrem BitBox, um REALU über den BrokerBot in ZCHF zu tauschen.",
   "sellBitboxSwapFrom": "Sie senden",
+  "sellBitboxSwapping": "Tausch on-chain. Bestätigen Sie auf der Bitbox.",
   "sellBitboxSwapTitle": "REALU → ZCHF tauschen",
   "sellBitboxSwapTo": "Sie erhalten",
-  "sellBitboxSwapping": "Tausch on-chain. Bestätigen Sie auf der Bitbox.",
   "sellBitboxWaitingForEth": "Gasgebühren werden angefordert",
   "sellBitboxWaitingForEthDescription": "Ein kleiner ETH-Betrag wird an Ihr Wallet gesendet, um die Transaktionsgebühren zu decken. Dies kann einige Minuten dauern.",
   "sellMinAmount": "Mindestbetrag: ${amount} ${currency}",
@@ -282,10 +282,10 @@
   "settingsWalletBackupSubtitle1": "Bitte notieren Sie Ihre 12 Wiederherstellungs-Wörter in der exakten Reihenfolge auf einem Blatt Papier und bewahren Sie sie absolut sicher auf.",
   "settingsWalletBackupSubtitle2": "Dies ist die einzige Möglichkeit, Ihre Wallet wiederherzustellen.",
   "showSeed": "Seed anzeigen",
-  "signMessage": "Signierte Nachricht",
-  "signMessageGet": "Signierte Nachricht abrufen",
   "signature": "Signatur",
   "signingCancelled": "Signatur abgebrochen — bitte BitBox erneut bestätigen",
+  "signMessage": "Signierte Nachricht",
+  "signMessageGet": "Signierte Nachricht abrufen",
   "skip": "Überspringen",
   "softwareTermsText": "Mit der Nutzung dieser App akzeptieren Sie die Nutzungsbedingungen dieser Software.",
   "softwareTermsTextHighlighted": "Nutzungsbedingungen",
@@ -329,9 +329,9 @@
   "transactionBuy": "Kauf",
   "transactionHistory": "Transaktionshistorie",
   "transactionPending": "In Bearbeitung",
+  "transactions": "Transaktionen",
   "transactionSell": "Verkauf",
   "transactionWaitingForPayment": "Warte auf Zahlung",
-  "transactions": "Transaktionen",
   "twoFa": "2-Faktor Authentifizierung",
   "twoFaCodeRequired": "Code ist erforderlich",
   "twoFaCodeTooShort": "Der Code sollte 6 Ziffern lang sein",
@@ -356,4 +356,4 @@
   "youPay": "Sie bezahlen",
   "youReceive": "Sie erhalten",
   "youSell": "Sie verkaufen"
-}
+}
\ No newline at end of file
diff --git a/assets/languages/strings_en.arb b/assets/languages/strings_en.arb
index 56e4db7f..bd63560a 100644
--- a/assets/languages/strings_en.arb
+++ b/assets/languages/strings_en.arb
@@ -33,8 +33,8 @@
   "buyPaymentConfirmFailedAktionariat": "There is a technical problem. Please check your email inbox — you may still need to confirm your blockchain address. Otherwise, please try again later. If the error persists, contact our support team.",
   "buyPaymentInformation": "Payment information",
   "buyPaymentInformationDescription": "Please transfer the purchase amount using your banking app with these details. The purpose of payment is important!",
-  "buyRealUnit": "Buy RealUnit",
   "buyRealu": "Buy RealUnit Token",
+  "buyRealUnit": "Buy RealUnit",
   "cancel": "Cancel",
   "changeAddress": "Change address",
   "changeInReview": "Change in review",
@@ -53,11 +53,11 @@
   "connectBitboxContent": "Please connect your BitBox with your Smartphone.",
   "connectBitboxContentIos": "Please connect your BitBox with your Smartphone and activate Bluetooth.",
   "connectBitboxFailed": "Something went wrong. Please try to connect again.",
-  "connectBitboxSignInHint": "After verifying the code, the BitBox will ask for one additional confirmation to sign you in.",
   "connectBitboxSignatureCapturing": "Please confirm the sign-in request on your BitBox device. This signature is captured once so future purchases won't need your BitBox again.",
   "connectBitboxSignatureCapturingTitle": "Confirm sign-in",
   "connectBitboxSignatureFailed": "We couldn't capture your sign-in signature. You can retry, or continue anyway – your BitBox may then be needed again for your first purchase.",
   "connectBitboxSignatureFailedTitle": "Sign-in not completed",
+  "connectBitboxSignInHint": "After verifying the code, the BitBox will ask for one additional confirmation to sign you in.",
   "connectBitboxTitle": "Connect BitBox",
   "connected": "Connected",
   "connectedBitboxContent": "Please confirm and follow the last steps on your BitBox.",
@@ -197,8 +197,8 @@
   "proofDocument": "Proof document",
   "purposeOfPayment": "Purpose of payment",
   "qrCode": "QR code",
-  "realunitStockToken": "RealUnit Stock Token",
   "realunitStockprice": "RealUnit Stockprice",
+  "realunitStockToken": "RealUnit Stock Token",
   "realunitWallet": "RealUnit Wallet",
   "realunitWalletLogout": "Log out of REALU Wallet",
   "realunitWalletLogoutCheck": "I have backed up my recovery phrase.",
@@ -246,18 +246,18 @@
   "sellBitboxCheckingEth": "Checking your wallet balance",
   "sellBitboxDepositDescription": "Confirm on your BitBox to transfer ZCHF to the DFX deposit address.",
   "sellBitboxDepositFrom": "You send",
+  "sellBitboxDepositing": "Sending ZCHF. Please confirm on the Bitbox.",
   "sellBitboxDepositRetryDescription": "The swap was completed but the ZCHF deposit could not be sent. Your funds are safe. Tap retry to try again.",
   "sellBitboxDepositRetryTitle": "Deposit failed",
   "sellBitboxDepositTitle": "Send ZCHF to DFX",
   "sellBitboxDepositTo": "DFX deposit",
-  "sellBitboxDepositing": "Sending ZCHF. Please confirm on the Bitbox.",
   "sellBitboxEthReady": "Wallet ready",
   "sellBitboxEthReadyDescription": "Your wallet has enough ETH to proceed with the sale.",
   "sellBitboxSwapDescription": "Confirm on your BitBox to swap REALU for ZCHF via the BrokerBot.",
   "sellBitboxSwapFrom": "You send",
+  "sellBitboxSwapping": "Swapping on-chain. Please confirm on the Bitbox.",
   "sellBitboxSwapTitle": "Swap REALU → ZCHF",
   "sellBitboxSwapTo": "You receive",
-  "sellBitboxSwapping": "Swapping on-chain. Please confirm on the Bitbox.",
   "sellBitboxWaitingForEth": "Requesting gas funds",
   "sellBitboxWaitingForEthDescription": "A small amount of ETH is being sent to your wallet to cover transaction fees. This may take a few minutes.",
   "sellMinAmount": "Minimum amount: ${amount} ${currency}",
@@ -282,10 +282,10 @@
   "settingsWalletBackupSubtitle1": "Please write down your 12 recovery words in the exact order on a piece of paper and keep them in a completely safe place.",
   "settingsWalletBackupSubtitle2": "This is the only way to recover your wallet.",
   "showSeed": "Show Seed",
-  "signMessage": "Sign Message",
-  "signMessageGet": "Get Sign Message",
   "signature": "Signature",
   "signingCancelled": "Signature cancelled — please confirm on the BitBox again",
+  "signMessage": "Sign Message",
+  "signMessageGet": "Get Sign Message",
   "skip": "Skip",
   "softwareTermsText": "By using this app, you accept the terms of use of this software.",
   "softwareTermsTextHighlighted": "terms of use",
@@ -329,9 +329,9 @@
   "transactionBuy": "Buy",
   "transactionHistory": "Transaction history",
   "transactionPending": "Processing",
+  "transactions": "Transactions",
   "transactionSell": "Sell",
   "transactionWaitingForPayment": "Waiting for payment",
-  "transactions": "Transactions",
   "twoFa": "Two-factor authentication",
   "twoFaCodeRequired": "Code is required",
   "twoFaCodeTooShort": "Code should be 6 digits",
@@ -356,4 +356,4 @@
   "youPay": "You pay",
   "youReceive": "You receive",
   "youSell": "You sell"
-}
+}
\ No newline at end of file
diff --git a/lib/packages/config/legal_documents_config.dart b/lib/packages/config/legal_documents_config.dart
index 06176595..e18a7dfe 100644
--- a/lib/packages/config/legal_documents_config.dart
+++ b/lib/packages/config/legal_documents_config.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
@@ -144,13 +146,15 @@ class WebDocumentConfig implements DocumentConfig {
   @override
   void onTap(BuildContext context) {
     if (openExternally) {
-      launchUrl(Uri.parse(url(context)), mode: LaunchMode.externalApplication);
+      unawaited(launchUrl(Uri.parse(url(context)), mode: LaunchMode.externalApplication));
     } else {
-      context.pushNamed(
-        AppRoutes.webView,
-        extra: WebViewRouteParams(
-          title: title(context),
-          url: Uri.parse(url(context)),
+      unawaited(
+        context.pushNamed(
+          AppRoutes.webView,
+          extra: WebViewRouteParams(
+            title: title(context),
+            url: Uri.parse(url(context)),
+          ),
         ),
       );
     }
diff --git a/lib/packages/service/transaction_history_service.dart b/lib/packages/service/transaction_history_service.dart
index 18fdafbc..b28dcba3 100644
--- a/lib/packages/service/transaction_history_service.dart
+++ b/lib/packages/service/transaction_history_service.dart
@@ -129,6 +129,7 @@ extension ToEpiAddress on String {
   String get asHexEip55 => EthereumAddress.fromHex(this).hexEip55;
 
   String get asShortTxId {
+    // realunit-lint:ignore fixed_index_address_substring — a tx id is always a 66-char hash; truncation for display.
     return '${substring(0, 10)}...${substring(length - 10)}';
   }
 }
diff --git a/lib/screens/buy/buy_page.dart b/lib/screens/buy/buy_page.dart
index a6d6b9e9..36c357f8 100644
--- a/lib/screens/buy/buy_page.dart
+++ b/lib/screens/buy/buy_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/generated/i18n.dart';
@@ -18,9 +20,11 @@ class BuyPage extends StatelessWidget {
     return MultiBlocProvider(
       providers: [
         BlocProvider(
-          create: (_) => BuyConverterCubit(
-            getIt<DfxBrokerbotService>(),
-          )..onFiatChanged('300'),
+          create: (_) {
+            final cubit = BuyConverterCubit(getIt<DfxBrokerbotService>());
+            unawaited(cubit.onFiatChanged('300'));
+            return cubit;
+          },
         ),
         BlocProvider(
           create: (_) => BuyPaymentInfoCubit(
@@ -57,9 +61,11 @@ class _BuyViewState extends State<BuyView> {
         listener: (context, state) {
           _syncController(_amountController, state.fiatText);
           _syncController(_resultController, state.sharesText);
-          context.read<BuyPaymentInfoCubit>().getPaymentInfo(
-            amount: _amountController.text,
-            currency: state.currency,
+          unawaited(
+            context.read<BuyPaymentInfoCubit>().getPaymentInfo(
+              amount: _amountController.text,
+              currency: state.currency,
+            ),
           );
         },
         builder: (context, state) {
diff --git a/lib/screens/buy/widgets/payment_converter.dart b/lib/screens/buy/widgets/payment_converter.dart
index 4f9d0f9c..5323a5fa 100644
--- a/lib/screens/buy/widgets/payment_converter.dart
+++ b/lib/screens/buy/widgets/payment_converter.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer;
 
 import 'package:flutter/material.dart';
@@ -39,32 +40,34 @@ class _PaymentConverterState extends State<PaymentConverter> {
   @override
   void initState() {
     super.initState();
-    getIt<SupportedFiatRepository>().getBuyable().then(
-      (currencies) {
-        if (mounted) setState(() => _buyable = currencies);
-      },
-      onError: (Object error, StackTrace stack) {
-        developer.log(
-          'PaymentConverter: failed to load buyable currencies — picker will '
-          'be disabled and the user is notified',
-          name: 'realunit_wallet.buy',
-          error: error,
-          stackTrace: stack,
-          level: 1000, // SEVERE
-        );
-        if (!mounted) return;
-        setState(() => _loadFailed = true);
-        // Defer to post-frame so we have a Scaffold ancestor in scope.
-        WidgetsBinding.instance.addPostFrameCallback((_) {
-          if (!mounted) return;
-          ScaffoldMessenger.of(context).showSnackBar(
-            SnackBar(
-              content: Text(S.of(context).settingsCurrencyLoadFailed),
-              backgroundColor: RealUnitColors.status.red600,
-            ),
+    unawaited(
+      getIt<SupportedFiatRepository>().getBuyable().then(
+        (currencies) {
+          if (mounted) setState(() => _buyable = currencies);
+        },
+        onError: (Object error, StackTrace stack) {
+          developer.log(
+            'PaymentConverter: failed to load buyable currencies — picker will '
+            'be disabled and the user is notified',
+            name: 'realunit_wallet.buy',
+            error: error,
+            stackTrace: stack,
+            level: 1000, // SEVERE
           );
-        });
-      },
+          if (!mounted) return;
+          setState(() => _loadFailed = true);
+          // Defer to post-frame so we have a Scaffold ancestor in scope.
+          WidgetsBinding.instance.addPostFrameCallback((_) {
+            if (!mounted) return;
+            ScaffoldMessenger.of(context).showSnackBar(
+              SnackBar(
+                content: Text(S.of(context).settingsCurrencyLoadFailed),
+                backgroundColor: RealUnitColors.status.red600,
+              ),
+            );
+          });
+        },
+      ),
     );
   }
 
@@ -131,7 +134,9 @@ class _PaymentConverterState extends State<PaymentConverter> {
                           initialValue: state.currency,
                           onSelected: (currency) {
                             if (currency == state.currency) return;
-                            context.read<BuyConverterCubit>().onCurrencyChanged(currency);
+                            unawaited(
+                              context.read<BuyConverterCubit>().onCurrencyChanged(currency),
+                            );
                           },
                           itemBuilder: (context) => _buyable.map((currency) {
                             return PopupMenuItem(
diff --git a/lib/screens/create_wallet/create_wallet_view.dart b/lib/screens/create_wallet/create_wallet_view.dart
index 4d9f174e..90160de8 100644
--- a/lib/screens/create_wallet/create_wallet_view.dart
+++ b/lib/screens/create_wallet/create_wallet_view.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -21,7 +23,7 @@ class CreateWalletView extends StatefulWidget {
 class _CreateWalletViewState extends State<CreateWalletView> {
   @override
   void initState() {
-    NoScreenshot.instance.screenshotOff();
+    unawaited(NoScreenshot.instance.screenshotOff());
     super.initState();
   }
 
@@ -102,7 +104,7 @@ class _CreateWalletViewState extends State<CreateWalletView> {
 
   @override
   void dispose() {
-    NoScreenshot.instance.screenshotOn();
+    unawaited(NoScreenshot.instance.screenshotOn());
     super.dispose();
   }
 }
diff --git a/lib/screens/dashboard/bloc/balance_cubit.dart b/lib/screens/dashboard/bloc/balance_cubit.dart
index c89d39de..f5a099b3 100644
--- a/lib/screens/dashboard/bloc/balance_cubit.dart
+++ b/lib/screens/dashboard/bloc/balance_cubit.dart
@@ -28,7 +28,7 @@ class BalanceCubit extends Cubit<Balance> {
 
   @override
   Future<void> close() {
-    _subscription?.cancel();
+    unawaited(_subscription?.cancel());
     return super.close();
   }
 }
diff --git a/lib/screens/dashboard/bloc/dashboard_transaction_history_cubit.dart b/lib/screens/dashboard/bloc/dashboard_transaction_history_cubit.dart
index b6b13bc6..ce229076 100644
--- a/lib/screens/dashboard/bloc/dashboard_transaction_history_cubit.dart
+++ b/lib/screens/dashboard/bloc/dashboard_transaction_history_cubit.dart
@@ -21,7 +21,7 @@ class DashboardTransactionHistoryCubit extends Cubit<List<Transaction>> {
 
   @override
   Future<void> close() {
-    _subscription.cancel();
+    unawaited(_subscription.cancel());
     return super.close();
   }
 }
diff --git a/lib/screens/dashboard/bloc/pending_transactions_cubit.dart b/lib/screens/dashboard/bloc/pending_transactions_cubit.dart
index 7db47c80..d3c8d45d 100644
--- a/lib/screens/dashboard/bloc/pending_transactions_cubit.dart
+++ b/lib/screens/dashboard/bloc/pending_transactions_cubit.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer show log;
 
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -6,7 +7,7 @@ import 'package:realunit_wallet/packages/service/transaction_history_service.dar
 
 class PendingTransactionsCubit extends Cubit<List<TransactionDto>> {
   PendingTransactionsCubit(this._transactionHistoryService) : super([]) {
-    _loadPendingTransactions();
+    unawaited(_loadPendingTransactions());
   }
 
   final TransactionHistoryService _transactionHistoryService;
diff --git a/lib/screens/debug_auth/debug_auth_view.dart b/lib/screens/debug_auth/debug_auth_view.dart
index 918cd668..4dd444b5 100644
--- a/lib/screens/debug_auth/debug_auth_view.dart
+++ b/lib/screens/debug_auth/debug_auth_view.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -73,8 +75,10 @@ class _DebugAuthViewState extends State<DebugAuthView> {
                 ),
                 GestureDetector(
                   onTap: () {
-                    Clipboard.setData(
-                      ClipboardData(text: state.signMessage!),
+                    unawaited(
+                      Clipboard.setData(
+                        ClipboardData(text: state.signMessage!),
+                      ),
                     );
                     ScaffoldMessenger.of(context).showSnackBar(
                       SnackBar(
diff --git a/lib/screens/hardware_connect_bitbox/bloc/connect_bitbox_cubit.dart b/lib/screens/hardware_connect_bitbox/bloc/connect_bitbox_cubit.dart
index 26cdc5a7..9b6ce9a4 100644
--- a/lib/screens/hardware_connect_bitbox/bloc/connect_bitbox_cubit.dart
+++ b/lib/screens/hardware_connect_bitbox/bloc/connect_bitbox_cubit.dart
@@ -35,7 +35,7 @@ class ConnectBitboxCubit extends Cubit<BitboxConnectionState> {
        _createWalletTimeout = createWalletTimeout,
        _pairingPinTimeout = pairingPinTimeout,
        super(BitboxNotConnected()) {
-    _startScanning();
+    unawaited(_startScanning());
   }
 
   final Duration _confirmPairingTimeout;
diff --git a/lib/screens/home/bloc/home_bloc.dart b/lib/screens/home/bloc/home_bloc.dart
index 0e97f15f..6257c7e3 100644
--- a/lib/screens/home/bloc/home_bloc.dart
+++ b/lib/screens/home/bloc/home_bloc.dart
@@ -129,8 +129,8 @@ class HomeBloc extends Bloc<HomeEvent, HomeState> {
 
   void _updateWallet(AWallet wallet) {
     _appStore.wallet = wallet;
-    _balanceService.updateBalance(_appStore.primaryAddress);
+    unawaited(_balanceService.updateBalance(_appStore.primaryAddress));
     _balanceService.startSync(_appStore.primaryAddress);
-    _transactionHistoryService.apiBasedSync();
+    unawaited(_transactionHistoryService.apiBasedSync());
   }
 }
diff --git a/lib/screens/kyc/kyc_page_manager.dart b/lib/screens/kyc/kyc_page_manager.dart
index 93694a3f..604634c1 100644
--- a/lib/screens/kyc/kyc_page_manager.dart
+++ b/lib/screens/kyc/kyc_page_manager.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/generated/i18n.dart';
@@ -31,11 +33,15 @@ class KycPageManager extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return BlocProvider(
-      create: (_) => KycCubit(
-        getIt<DfxKycService>(),
-        getIt<RealUnitRegistrationService>(),
-        getIt<AppStore>(),
-      )..checkKyc(context: kycContext),
+      create: (_) {
+        final cubit = KycCubit(
+          getIt<DfxKycService>(),
+          getIt<RealUnitRegistrationService>(),
+          getIt<AppStore>(),
+        );
+        unawaited(cubit.checkKyc(context: kycContext));
+        return cubit;
+      },
       child: const KycViewManager(),
     );
   }
@@ -67,7 +73,7 @@ class KycViewManager extends StatelessWidget {
             KycStep.legalDisclaimer => LegalDisclaimerPage(
               onCompleted: () {
                 context.read<KycCubit>().markLegalDisclaimerAccepted();
-                context.read<KycCubit>().checkKyc();
+                unawaited(context.read<KycCubit>().checkKyc());
               },
             ),
             KycStep.registration => KycRegistrationPage(initialUserData: realUnitUserData),
@@ -79,8 +85,7 @@ class KycViewManager extends StatelessWidget {
             // Exhaustive over KycStep so a new value is a compile error here
             // (forced handling) rather than a silent blank Scaffold. dfxApproval
             // was the missing case that fell through to the old blank fallback.
-            KycStep.dfxApproval =>
-              const KycPendingPage(pendingStep: KycStep.dfxApproval),
+            KycStep.dfxApproval => const KycPendingPage(pendingStep: KycStep.dfxApproval),
           },
         KycState() => const Scaffold(),
       },
diff --git a/lib/screens/kyc/steps/2fa/kyc_2fa_page.dart b/lib/screens/kyc/steps/2fa/kyc_2fa_page.dart
index cf317672..70666ff1 100644
--- a/lib/screens/kyc/steps/2fa/kyc_2fa_page.dart
+++ b/lib/screens/kyc/steps/2fa/kyc_2fa_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/generated/i18n.dart';
@@ -48,7 +50,7 @@ class _Kyc2FaViewState extends State<Kyc2FaView> {
 
   @override
   void initState() {
-    context.read<Kyc2FaCubit>().requestCode();
+    unawaited(context.read<Kyc2FaCubit>().requestCode());
     super.initState();
   }
 
@@ -61,7 +63,7 @@ class _Kyc2FaViewState extends State<Kyc2FaView> {
           BlocListener<Kyc2FaVerifyCubit, Kyc2FaVerifyState>(
             listener: (context, state) {
               if (state is Kyc2FaVerifySuccess) {
-                context.read<KycCubit>().checkKyc();
+                unawaited(context.read<KycCubit>().checkKyc());
               }
               if (state is Kyc2FaVerifyFailure) {
                 ScaffoldMessenger.of(context).showSnackBar(
@@ -136,7 +138,9 @@ class _Kyc2FaViewState extends State<Kyc2FaView> {
                               state: state is Kyc2FaVerifyLoading ? .loading : .idle,
                               onPressed: () {
                                 if (_formKey.currentState?.validate() ?? false) {
-                                  context.read<Kyc2FaVerifyCubit>().verifyCode(codeCtrl.text);
+                                  unawaited(
+                                    context.read<Kyc2FaVerifyCubit>().verifyCode(codeCtrl.text),
+                                  );
                                 }
                               },
                               label: S.of(context).next,
diff --git a/lib/screens/kyc/steps/email/kyc_email_page.dart b/lib/screens/kyc/steps/email/kyc_email_page.dart
index 11f399fb..7ea9d3de 100644
--- a/lib/screens/kyc/steps/email/kyc_email_page.dart
+++ b/lib/screens/kyc/steps/email/kyc_email_page.dart
@@ -126,8 +126,10 @@ class _KycEmailFormState extends State<KycEmailForm> {
                           onPressed: () {
                             FocusManager.instance.primaryFocus?.unfocus();
                             if (_formKey.currentState?.validate() ?? false) {
-                              context.read<KycEmailStepCubit>().registerEmail(
-                                _emailCtrl.text.trim(),
+                              unawaited(
+                                context.read<KycEmailStepCubit>().registerEmail(
+                                  _emailCtrl.text.trim(),
+                                ),
                               );
                             }
                           },
diff --git a/lib/screens/kyc/steps/financial_data/kyc_financial_data_page.dart b/lib/screens/kyc/steps/financial_data/kyc_financial_data_page.dart
index 647b89da..40c0c5c9 100644
--- a/lib/screens/kyc/steps/financial_data/kyc_financial_data_page.dart
+++ b/lib/screens/kyc/steps/financial_data/kyc_financial_data_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/packages/service/dfx/dfx_kyc_service.dart';
@@ -18,13 +20,16 @@ class KycFinancialDataPage extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return BlocProvider(
-      create: (_) =>
-          KycFinancialDataCubit(
-            getIt<DfxKycService>(),
-          )..loadQuestions(
+      create: (_) {
+        final cubit = KycFinancialDataCubit(getIt<DfxKycService>());
+        unawaited(
+          cubit.loadQuestions(
             url,
             language: context.read<SettingsBloc>().state.language,
           ),
+        );
+        return cubit;
+      },
       child: const KycFinancialDataView(),
     );
   }
@@ -38,7 +43,7 @@ class KycFinancialDataView extends StatelessWidget {
     return BlocListener<KycFinancialDataCubit, KycFinancialDataState>(
       listener: (context, state) {
         if (state is KycFinancialDataSubmitSuccess) {
-          context.read<KycCubit>().checkKyc();
+          unawaited(context.read<KycCubit>().checkKyc());
         }
         if (state is KycFinancialDataFailure) {
           ScaffoldMessenger.of(context).showSnackBar(
diff --git a/lib/screens/kyc/steps/ident/kyc_ident_page.dart b/lib/screens/kyc/steps/ident/kyc_ident_page.dart
index 0339f9bb..47983032 100644
--- a/lib/screens/kyc/steps/ident/kyc_ident_page.dart
+++ b/lib/screens/kyc/steps/ident/kyc_ident_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/generated/i18n.dart';
@@ -41,7 +43,7 @@ class KycIdentView extends StatelessWidget {
         child: BlocListener<KycIdentCubit, KycIdentState>(
           listener: (context, state) {
             if (state is KycIdentSuccess) {
-              context.read<KycCubit>().checkKyc();
+              unawaited(context.read<KycCubit>().checkKyc());
             }
             if (state is KycIdentFailure) {
               if (state.status == FailureStatus.finallyRejected) {
@@ -121,9 +123,11 @@ class KycIdentView extends StatelessWidget {
                         return AppFilledButton(
                           state: state is KycIdentLoading ? .loading : .idle,
                           onPressed: () {
-                            context.read<KycIdentCubit>().startIdent(
-                              accessToken,
-                              localeCode: context.read<SettingsBloc>().state.language.code,
+                            unawaited(
+                              context.read<KycIdentCubit>().startIdent(
+                                accessToken,
+                                localeCode: context.read<SettingsBloc>().state.language.code,
+                              ),
                             );
                           },
                           label: S.of(context).next,
diff --git a/lib/screens/kyc/steps/link_wallet/kyc_link_wallet_page.dart b/lib/screens/kyc/steps/link_wallet/kyc_link_wallet_page.dart
index 79f82e72..89e14e98 100644
--- a/lib/screens/kyc/steps/link_wallet/kyc_link_wallet_page.dart
+++ b/lib/screens/kyc/steps/link_wallet/kyc_link_wallet_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -52,7 +54,7 @@ class KycLinkWalletView extends StatelessWidget {
             // Aktionariat share register, so `getRegistrationInfo` will return
             // `AlreadyRegistered` and `_runCheckKyc` will dispatch the next
             // KYC step.
-            context.read<KycCubit>().checkKyc();
+            unawaited(context.read<KycCubit>().checkKyc());
           }
           if (state is KycLinkWalletFailure) {
             ScaffoldMessenger.of(context).showSnackBar(
diff --git a/lib/screens/kyc/steps/nationality/kyc_nationality_page.dart b/lib/screens/kyc/steps/nationality/kyc_nationality_page.dart
index bdb7c632..54509957 100644
--- a/lib/screens/kyc/steps/nationality/kyc_nationality_page.dart
+++ b/lib/screens/kyc/steps/nationality/kyc_nationality_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/generated/i18n.dart';
@@ -46,7 +48,7 @@ class _KycNationalityViewState extends State<KycNationalityView> {
       body: BlocListener<KycNationalityCubit, KycNationalityState>(
         listener: (context, state) {
           if (state is KycNationalitySuccess) {
-            context.read<KycCubit>().checkKyc();
+            unawaited(context.read<KycCubit>().checkKyc());
           }
           if (state is KycNationalityFailure) {
             ScaffoldMessenger.of(context).showSnackBar(
@@ -81,9 +83,11 @@ class _KycNationalityViewState extends State<KycNationalityView> {
                             state: state is KycNationalityLoading ? .loading : .idle,
                             onPressed: () {
                               if (_formKey.currentState?.validate() ?? false) {
-                                context.read<KycNationalityCubit>().registerNationality(
-                                  url: widget.url,
-                                  nationality: nationalityCtrl.value!,
+                                unawaited(
+                                  context.read<KycNationalityCubit>().registerNationality(
+                                    url: widget.url,
+                                    nationality: nationalityCtrl.value!,
+                                  ),
                                 );
                               }
                             },
diff --git a/lib/screens/kyc/steps/registration/kyc_registration_page.dart b/lib/screens/kyc/steps/registration/kyc_registration_page.dart
index e4ee5bff..38357443 100644
--- a/lib/screens/kyc/steps/registration/kyc_registration_page.dart
+++ b/lib/screens/kyc/steps/registration/kyc_registration_page.dart
@@ -85,10 +85,12 @@ class _KycRegistrationViewState extends State<KycRegistrationView> {
   void initState() {
     super.initState();
     _stepSubscription = context.read<KycRegistrationStepCubit>().stream.listen((state) {
-      _pageController.animateToPage(
-        state.index,
-        duration: const Duration(milliseconds: 350),
-        curve: Curves.easeOut,
+      unawaited(
+        _pageController.animateToPage(
+          state.index,
+          duration: const Duration(milliseconds: 350),
+          curve: Curves.easeOut,
+        ),
       );
     });
 
@@ -277,12 +279,15 @@ class _KycRegistrationViewState extends State<KycRegistrationView> {
     addressPostalCode: postalCodeCtrl.text.trim(),
     addressCity: cityCtrl.text.trim(),
     addressCountry: countryCtrl.value!,
+    // realunit-lint:ignore hardcoded_swiss_tax_residence — this registration step is the
+    // Swiss-resident path; the literal is intentional here. Flagged for product review of
+    // whether a non-Swiss path must set this from user input. Baselined, not silently fixed.
     swissTaxResidence: true,
   );
 
   @override
   void dispose() {
-    _stepSubscription?.cancel();
+    unawaited(_stepSubscription?.cancel());
     _pageController.dispose();
     typeCtrl.dispose();
     firstnameCtrl.dispose();
diff --git a/lib/screens/legal/subpages/legal_document_page.dart b/lib/screens/legal/subpages/legal_document_page.dart
index 4994b730..a471ed28 100644
--- a/lib/screens/legal/subpages/legal_document_page.dart
+++ b/lib/screens/legal/subpages/legal_document_page.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer;
 
 import 'package:flutter/material.dart';
@@ -52,7 +53,7 @@ class _LegalDocumentPageState extends State<LegalDocumentPage> {
     if (widget.initialMarkdownContent != null) {
       _markdownContent = widget.initialMarkdownContent;
     } else {
-      _loadMarkdown();
+      unawaited(_loadMarkdown());
     }
   }
 
@@ -81,7 +82,7 @@ class _LegalDocumentPageState extends State<LegalDocumentPage> {
       _loadFailed = false;
       _markdownContent = null;
     });
-    _loadMarkdown();
+    unawaited(_loadMarkdown());
   }
 
   String? get _pdfUrl {
@@ -108,11 +109,13 @@ class _LegalDocumentPageState extends State<LegalDocumentPage> {
                   ),
                   onTapLink: (text, href, title) {
                     if (href == null || href.startsWith('mailto:') || href.contains('@')) return;
-                    context.pushNamed(
-                      AppRoutes.webView,
-                      extra: WebViewRouteParams(
-                        title: text,
-                        url: Uri.parse(href),
+                    unawaited(
+                      context.pushNamed(
+                        AppRoutes.webView,
+                        extra: WebViewRouteParams(
+                          title: text,
+                          url: Uri.parse(href),
+                        ),
                       ),
                     );
                   },
diff --git a/lib/screens/pin/bloc/setup_pin/setup_pin_cubit.dart b/lib/screens/pin/bloc/setup_pin/setup_pin_cubit.dart
index 11e77ac5..3a822a72 100644
--- a/lib/screens/pin/bloc/setup_pin/setup_pin_cubit.dart
+++ b/lib/screens/pin/bloc/setup_pin/setup_pin_cubit.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:equatable/equatable.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/packages/service/biometric_service.dart';
@@ -52,7 +54,7 @@ class SetupPinCubit extends Cubit<SetupPinState> {
         );
         break;
       case SetupPinMode.confirm:
-        _confirmPin(pin);
+        unawaited(_confirmPin(pin));
         break;
     }
   }
diff --git a/lib/screens/pin/bloc/verify_pin/verify_pin_cubit.dart b/lib/screens/pin/bloc/verify_pin/verify_pin_cubit.dart
index 8a43a36b..c02d0ee8 100644
--- a/lib/screens/pin/bloc/verify_pin/verify_pin_cubit.dart
+++ b/lib/screens/pin/bloc/verify_pin/verify_pin_cubit.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:equatable/equatable.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/packages/service/biometric_service.dart';
@@ -23,7 +25,7 @@ class VerifyPinCubit extends Cubit<VerifyPinState> {
     if (state is VerifyPinTemporarilyLocked || state is VerifyPinLocked) return;
     if (state.pin.length == pinLength) return;
     emit(state.copyWith(pin: '${state.pin}$digit'));
-    if (state.pin.length == pinLength) checkPin();
+    if (state.pin.length == pinLength) unawaited(checkPin());
   }
 
   void deleteDigit() {
diff --git a/lib/screens/pin/verify_pin_page.dart b/lib/screens/pin/verify_pin_page.dart
index f0af94a9..3584a876 100644
--- a/lib/screens/pin/verify_pin_page.dart
+++ b/lib/screens/pin/verify_pin_page.dart
@@ -83,7 +83,7 @@ class _VerifyPinViewState extends State<VerifyPinView> {
   void initState() {
     super.initState();
     WidgetsBinding.instance.addPostFrameCallback((_) {
-      context.read<VerifyPinCubit>().checkBiometricAvailability();
+      unawaited(context.read<VerifyPinCubit>().checkBiometricAvailability());
     });
   }
 
diff --git a/lib/screens/receive/widgets/qr_address_widget.dart b/lib/screens/receive/widgets/qr_address_widget.dart
index 677ba900..19700468 100644
--- a/lib/screens/receive/widgets/qr_address_widget.dart
+++ b/lib/screens/receive/widgets/qr_address_widget.dart
@@ -38,16 +38,24 @@ class QRAddressWidget extends StatelessWidget {
               Text.rich(
                 TextSpan(
                   children: [
+                    // The fixed 0/6/21/36 slices assume `subtitle` is a full
+                    // 42-char EVM address — true at the only call site, but a
+                    // guarded slice is the better shape and is tracked as a
+                    // follow-up. Baselined below so the pattern guard blocks
+                    // NEW occurrences (this is the audit's RangeError site).
                     TextSpan(
+                      // realunit-lint:ignore fixed_index_address_substring — baselined audit site, see note above.
                       text: subtitle.substring(0, 6),
                       style: const TextStyle(fontWeight: .bold),
                     ),
                     const TextSpan(text: ' '),
                     TextSpan(
+                      // realunit-lint:ignore fixed_index_address_substring — baselined audit site, see note above.
                       text: subtitle.substring(6, 21),
                     ),
                     const TextSpan(text: '\n'),
                     TextSpan(
+                      // realunit-lint:ignore fixed_index_address_substring — baselined audit site, see note above.
                       text: subtitle.substring(21, 36),
                     ),
                     const TextSpan(text: ' '),
diff --git a/lib/screens/sell/cubits/sell_balance/sell_balance_cubit.dart b/lib/screens/sell/cubits/sell_balance/sell_balance_cubit.dart
index dc80bd20..c4eee03a 100644
--- a/lib/screens/sell/cubits/sell_balance/sell_balance_cubit.dart
+++ b/lib/screens/sell/cubits/sell_balance/sell_balance_cubit.dart
@@ -27,7 +27,7 @@ class SellBalanceCubit extends Cubit<Balance> {
 
   @override
   Future<void> close() {
-    _subscription?.cancel();
+    unawaited(_subscription?.cancel());
     return super.close();
   }
 }
diff --git a/lib/screens/sell/cubits/sell_bank_accounts/sell_bank_accounts_cubit.dart b/lib/screens/sell/cubits/sell_bank_accounts/sell_bank_accounts_cubit.dart
index 71ac82b1..5698a1c8 100644
--- a/lib/screens/sell/cubits/sell_bank_accounts/sell_bank_accounts_cubit.dart
+++ b/lib/screens/sell/cubits/sell_bank_accounts/sell_bank_accounts_cubit.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer;
 
 import 'package:equatable/equatable.dart';
@@ -14,7 +15,7 @@ class SellBankAccountsCubit extends Cubit<SellBankAccountsState> {
     DfxBankAccountService bankAccountService,
   ) : _dfxBankAccountService = bankAccountService,
       super(const SellBankAccountsInitial()) {
-    _loadBankAccounts();
+    unawaited(_loadBankAccounts());
   }
 
   Future<void> add({required String iban, String? label}) async {
diff --git a/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart b/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart
index 93660b47..d92ad072 100644
--- a/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart
+++ b/lib/screens/sell/cubits/sell_converter/sell_converter_cubit.dart
@@ -87,6 +87,10 @@ class SellConverterCubit extends Cubit<SellConverterState> {
     // the seq guard.
     emit(state.copyWith(loading: true, currency: currency));
     try {
+      // realunit-lint:ignore cross_flow_brokerbot_endpoint — current behaviour is pinned by
+      // sell_converter_cubit_test.dart ('onCurrencyChanged calls getBuyPrice (not getSellPrice)').
+      // Baselined and flagged for product review of whether the sell flow should price via
+      // getSellPrice on a currency change; not changed here to keep this PR behaviour-neutral.
       final result = await _brokerbotService.getBuyPrice(state.sharesText, currency);
       if (isClosed || mySeq != _seq) return;
       emit(
diff --git a/lib/screens/sell/sell_page.dart b/lib/screens/sell/sell_page.dart
index cf27a5de..bf4b0761 100644
--- a/lib/screens/sell/sell_page.dart
+++ b/lib/screens/sell/sell_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/generated/i18n.dart';
@@ -28,9 +30,11 @@ class SellPage extends StatelessWidget {
           ),
         ),
         BlocProvider(
-          create: (context) => SellConverterCubit(
-            getIt<DfxBrokerbotService>(),
-          )..onSharesChanged('100'),
+          create: (context) {
+            final cubit = SellConverterCubit(getIt<DfxBrokerbotService>());
+            unawaited(cubit.onSharesChanged('100'));
+            return cubit;
+          },
         ),
         BlocProvider(
           create: (context) => SellPaymentInfoCubit(
diff --git a/lib/screens/sell/widgets/sell_add_bank_account_sheet.dart b/lib/screens/sell/widgets/sell_add_bank_account_sheet.dart
index 9d1afccb..7685b020 100644
--- a/lib/screens/sell/widgets/sell_add_bank_account_sheet.dart
+++ b/lib/screens/sell/widgets/sell_add_bank_account_sheet.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
@@ -183,11 +185,13 @@ class _SellAddBankAccountSheetState extends State<SellAddBankAccountSheet> {
                             fullWidth: false,
                             onPressed: () {
                               if (_formKey.currentState?.validate() ?? false) {
-                                context.read<SellBankAccountsCubit>().add(
-                                  iban: _ibanController.text,
-                                  label: _nameController.text.isNotEmpty
-                                      ? _nameController.text
-                                      : null,
+                                unawaited(
+                                  context.read<SellBankAccountsCubit>().add(
+                                    iban: _ibanController.text,
+                                    label: _nameController.text.isNotEmpty
+                                        ? _nameController.text
+                                        : null,
+                                  ),
                                 );
                               }
                             },
diff --git a/lib/screens/sell/widgets/sell_converter.dart b/lib/screens/sell/widgets/sell_converter.dart
index 8fed74c4..30109a63 100644
--- a/lib/screens/sell/widgets/sell_converter.dart
+++ b/lib/screens/sell/widgets/sell_converter.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer;
 
 import 'package:flutter/material.dart';
@@ -41,31 +42,33 @@ class _SellConverterState extends State<SellConverter> {
   @override
   void initState() {
     super.initState();
-    getIt<SupportedFiatRepository>().getSellable().then(
-      (currencies) {
-        if (mounted) setState(() => _sellable = currencies);
-      },
-      onError: (Object error, StackTrace stack) {
-        developer.log(
-          'SellConverter: failed to load sellable currencies — picker will '
-          'be disabled and the user is notified',
-          name: 'realunit_wallet.sell',
-          error: error,
-          stackTrace: stack,
-          level: 1000, // SEVERE
-        );
-        if (!mounted) return;
-        setState(() => _loadFailed = true);
-        WidgetsBinding.instance.addPostFrameCallback((_) {
-          if (!mounted) return;
-          ScaffoldMessenger.of(context).showSnackBar(
-            SnackBar(
-              content: Text(S.of(context).settingsCurrencyLoadFailed),
-              backgroundColor: RealUnitColors.status.red600,
-            ),
+    unawaited(
+      getIt<SupportedFiatRepository>().getSellable().then(
+        (currencies) {
+          if (mounted) setState(() => _sellable = currencies);
+        },
+        onError: (Object error, StackTrace stack) {
+          developer.log(
+            'SellConverter: failed to load sellable currencies — picker will '
+            'be disabled and the user is notified',
+            name: 'realunit_wallet.sell',
+            error: error,
+            stackTrace: stack,
+            level: 1000, // SEVERE
           );
-        });
-      },
+          if (!mounted) return;
+          setState(() => _loadFailed = true);
+          WidgetsBinding.instance.addPostFrameCallback((_) {
+            if (!mounted) return;
+            ScaffoldMessenger.of(context).showSnackBar(
+              SnackBar(
+                content: Text(S.of(context).settingsCurrencyLoadFailed),
+                backgroundColor: RealUnitColors.status.red600,
+              ),
+            );
+          });
+        },
+      ),
     );
   }
 
@@ -127,7 +130,9 @@ class _SellConverterState extends State<SellConverter> {
                                 onTap: () {
                                   final maxStr = state.balance.toString();
                                   _amountController.text = maxStr;
-                                  context.read<SellConverterCubit>().onSharesChanged(maxStr);
+                                  unawaited(
+                                    context.read<SellConverterCubit>().onSharesChanged(maxStr),
+                                  );
                                 },
                               );
                             },
@@ -247,7 +252,9 @@ class _SellConverterState extends State<SellConverter> {
                           initialValue: state.currency,
                           onSelected: (currency) {
                             if (currency == state.currency) return;
-                            context.read<SellConverterCubit>().onCurrencyChanged(currency);
+                            unawaited(
+                              context.read<SellConverterCubit>().onCurrencyChanged(currency),
+                            );
                           },
                           itemBuilder: (context) => _sellable.map((currency) {
                             return PopupMenuItem(
diff --git a/lib/screens/sell_bitbox/widgets/sell_bitbox_deposit_step.dart b/lib/screens/sell_bitbox/widgets/sell_bitbox_deposit_step.dart
index c13decdf..7822460e 100644
--- a/lib/screens/sell_bitbox/widgets/sell_bitbox_deposit_step.dart
+++ b/lib/screens/sell_bitbox/widgets/sell_bitbox_deposit_step.dart
@@ -133,6 +133,7 @@ class SellBitboxDepositStep extends StatelessWidget {
 
   String _truncateAddress(String address) {
     if (address.length <= 12) return address;
+    // realunit-lint:ignore fixed_index_address_substring — guarded by the length check above (>12).
     return '${address.substring(0, 6)}…${address.substring(address.length - 4)}';
   }
 }
diff --git a/lib/screens/settings_contact/settings_contact_page.dart b/lib/screens/settings_contact/settings_contact_page.dart
index 04d20b40..c4751154 100644
--- a/lib/screens/settings_contact/settings_contact_page.dart
+++ b/lib/screens/settings_contact/settings_contact_page.dart
@@ -20,7 +20,11 @@ class SettingsContactPage extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return BlocProvider(
-      create: (_) => SettingsContactCubit(getIt<DfxKycService>())..init(),
+      create: (_) {
+        final cubit = SettingsContactCubit(getIt<DfxKycService>());
+        unawaited(cubit.init());
+        return cubit;
+      },
       child: const SettingsContactView(),
     );
   }
diff --git a/lib/screens/settings_seed/bloc/settings_seed_cubit.dart b/lib/screens/settings_seed/bloc/settings_seed_cubit.dart
index e7a80430..f4acc232 100644
--- a/lib/screens/settings_seed/bloc/settings_seed_cubit.dart
+++ b/lib/screens/settings_seed/bloc/settings_seed_cubit.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:equatable/equatable.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/packages/service/app_store.dart';
@@ -16,8 +18,8 @@ class SettingsSeedCubit extends Cubit<SettingsSeedState> {
   // briefly be empty, which trips MnemonicReadOnlyField's `length == 12`
   // assert and crashes the screen on open.
   SettingsSeedCubit(this._appStore, this._walletService)
-      : super(SettingsSeedState(_initialSeed(_appStore))) {
-    _loadSeed();
+    : super(SettingsSeedState(_initialSeed(_appStore))) {
+    unawaited(_loadSeed());
   }
 
   static String _initialSeed(AppStore store) {
diff --git a/lib/screens/settings_seed/settings_seed_view.dart b/lib/screens/settings_seed/settings_seed_view.dart
index 25f5fef0..9a7fad45 100644
--- a/lib/screens/settings_seed/settings_seed_view.dart
+++ b/lib/screens/settings_seed/settings_seed_view.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -19,7 +21,7 @@ class SettingsSeedView extends StatefulWidget {
 class _SettingsSeedViewState extends State<SettingsSeedView> {
   @override
   void initState() {
-    NoScreenshot.instance.screenshotOff();
+    unawaited(NoScreenshot.instance.screenshotOff());
     super.initState();
   }
 
@@ -114,7 +116,7 @@ class _SettingsSeedViewState extends State<SettingsSeedView> {
 
   @override
   void dispose() {
-    NoScreenshot.instance.screenshotOn();
+    unawaited(NoScreenshot.instance.screenshotOn());
     super.dispose();
   }
 }
diff --git a/lib/screens/settings_user_data/cubit/settings_user_data_cubit.dart b/lib/screens/settings_user_data/cubit/settings_user_data_cubit.dart
index 0fc09b62..381b025d 100644
--- a/lib/screens/settings_user_data/cubit/settings_user_data_cubit.dart
+++ b/lib/screens/settings_user_data/cubit/settings_user_data_cubit.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer;
 
 import 'package:equatable/equatable.dart';
@@ -34,7 +35,7 @@ class SettingsUserDataCubit extends Cubit<SettingsUserDataState> {
        _countryService = countryService,
        _kycService = kycService,
        super(const SettingsUserDataInitial()) {
-    getUserData();
+    unawaited(getUserData());
   }
 
   Future<void> getUserData() async {
diff --git a/lib/screens/settings_user_data/subpages/edit_address/cubit/settings_edit_address_cubit.dart b/lib/screens/settings_user_data/subpages/edit_address/cubit/settings_edit_address_cubit.dart
index fc6c1a5e..0785180f 100644
--- a/lib/screens/settings_user_data/subpages/edit_address/cubit/settings_edit_address_cubit.dart
+++ b/lib/screens/settings_user_data/subpages/edit_address/cubit/settings_edit_address_cubit.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:equatable/equatable.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/packages/service/dfx/dfx_kyc_service.dart';
@@ -11,7 +13,7 @@ class SettingsEditAddressCubit extends Cubit<SettingsEditAddressState> {
   SettingsEditAddressCubit({required DfxKycService kycService})
     : _kycService = kycService,
       super(const SettingsEditAddressInitial()) {
-    _loadEdit();
+    unawaited(_loadEdit());
   }
 
   Future<void> _loadEdit() async {
diff --git a/lib/screens/settings_user_data/subpages/edit_name/cubit/settings_edit_name_cubit.dart b/lib/screens/settings_user_data/subpages/edit_name/cubit/settings_edit_name_cubit.dart
index 12076192..2d549f13 100644
--- a/lib/screens/settings_user_data/subpages/edit_name/cubit/settings_edit_name_cubit.dart
+++ b/lib/screens/settings_user_data/subpages/edit_name/cubit/settings_edit_name_cubit.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:equatable/equatable.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/packages/service/dfx/dfx_kyc_service.dart';
@@ -11,7 +13,7 @@ class SettingsEditNameCubit extends Cubit<SettingsEditNameState> {
   SettingsEditNameCubit({required DfxKycService kycService})
     : _kycService = kycService,
       super(const SettingsEditNameInitial()) {
-    _loadEdit();
+    unawaited(_loadEdit());
   }
 
   Future<void> _loadEdit() async {
diff --git a/lib/screens/settings_user_data/subpages/edit_phone_number/settings_edit_phone_number_page.dart b/lib/screens/settings_user_data/subpages/edit_phone_number/settings_edit_phone_number_page.dart
index aaa2c99c..121a0e33 100644
--- a/lib/screens/settings_user_data/subpages/edit_phone_number/settings_edit_phone_number_page.dart
+++ b/lib/screens/settings_user_data/subpages/edit_phone_number/settings_edit_phone_number_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
@@ -108,7 +110,7 @@ class _SettingsEditPhoneNumberViewState extends State<SettingsEditPhoneNumberVie
     if (_formKey.currentState?.validate() ?? false) {
       final phone = _phoneCtrl.value;
       if (phone != null) {
-        context.read<SettingsEditPhoneNumberCubit>().editPhoneNumber(phone);
+        unawaited(context.read<SettingsEditPhoneNumberCubit>().editPhoneNumber(phone));
       }
     }
   }
diff --git a/lib/screens/support/cubits/support_chat/support_chat_cubit.dart b/lib/screens/support/cubits/support_chat/support_chat_cubit.dart
index 28e1d434..137645a0 100644
--- a/lib/screens/support/cubits/support_chat/support_chat_cubit.dart
+++ b/lib/screens/support/cubits/support_chat/support_chat_cubit.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer;
 
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -13,7 +14,7 @@ class SupportChatCubit extends Cubit<SupportChatState> {
     : _supportService = supportService,
       _ticketUid = ticketUid,
       super(const SupportChatInitial()) {
-    loadTicket();
+    unawaited(loadTicket());
   }
 
   Future<void> loadTicket() async {
diff --git a/lib/screens/support/cubits/support_tickets/support_tickets_cubit.dart b/lib/screens/support/cubits/support_tickets/support_tickets_cubit.dart
index b7156824..60349799 100644
--- a/lib/screens/support/cubits/support_tickets/support_tickets_cubit.dart
+++ b/lib/screens/support/cubits/support_tickets/support_tickets_cubit.dart
@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer' as developer;
 
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -13,7 +14,7 @@ class SupportTicketsCubit extends Cubit<SupportTicketsState> {
       super(
         const SupportTicketsInitial(),
       ) {
-    loadTickets();
+    unawaited(loadTickets());
   }
 
   Future<void> loadTickets() async {
diff --git a/lib/screens/support/subpages/support_chat_page.dart b/lib/screens/support/subpages/support_chat_page.dart
index 2269cbf9..02b2b57f 100644
--- a/lib/screens/support/subpages/support_chat_page.dart
+++ b/lib/screens/support/subpages/support_chat_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -77,7 +79,7 @@ class _SupportChatViewState extends State<SupportChatView> {
                     onSend: () {
                       final message = _messageController.text;
                       if (message.trim().isNotEmpty) {
-                        context.read<SupportChatCubit>().sendMessage(message);
+                        unawaited(context.read<SupportChatCubit>().sendMessage(message));
                         _messageController.clear();
                       }
                     },
@@ -101,10 +103,12 @@ class _SupportChatViewState extends State<SupportChatView> {
 
   void _scrollToBottom() {
     if (_scrollController.hasClients) {
-      _scrollController.animateTo(
-        _scrollController.position.maxScrollExtent,
-        duration: const Duration(milliseconds: 300),
-        curve: Curves.easeOut,
+      unawaited(
+        _scrollController.animateTo(
+          _scrollController.position.maxScrollExtent,
+          duration: const Duration(milliseconds: 300),
+          curve: Curves.easeOut,
+        ),
       );
     }
   }
diff --git a/lib/screens/support/subpages/support_email_capture_page.dart b/lib/screens/support/subpages/support_email_capture_page.dart
index 21f91858..c6540fe4 100644
--- a/lib/screens/support/subpages/support_email_capture_page.dart
+++ b/lib/screens/support/subpages/support_email_capture_page.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:realunit_wallet/generated/i18n.dart';
@@ -111,14 +113,14 @@ class _SupportEmailCaptureFormState extends State<SupportEmailCaptureForm> {
                   BlocBuilder<SupportEmailCaptureCubit, SupportEmailCaptureState>(
                     builder: (context, state) {
                       return AppFilledButton(
-                        state: state is SupportEmailCaptureLoading
-                            ? .loading
-                            : .idle,
+                        state: state is SupportEmailCaptureLoading ? .loading : .idle,
                         onPressed: () {
                           FocusManager.instance.primaryFocus?.unfocus();
                           if (_formKey.currentState?.validate() ?? false) {
-                            context.read<SupportEmailCaptureCubit>().submit(
-                              _emailCtrl.text.trim(),
+                            unawaited(
+                              context.read<SupportEmailCaptureCubit>().submit(
+                                _emailCtrl.text.trim(),
+                              ),
                             );
                           }
                         },
diff --git a/lib/screens/transaction_history/cubits/filter/transaction_history_filter_cubit.dart b/lib/screens/transaction_history/cubits/filter/transaction_history_filter_cubit.dart
index fbe743f1..6541a9b1 100644
--- a/lib/screens/transaction_history/cubits/filter/transaction_history_filter_cubit.dart
+++ b/lib/screens/transaction_history/cubits/filter/transaction_history_filter_cubit.dart
@@ -15,9 +15,11 @@ class TransactionHistoryFilterCubit extends Cubit<TransactionHistoryFilterState>
     required String walletAddress,
     int? limit,
   }) : super(TransactionHistoryFilterState()) {
-    _subscription = _repository.watchTransactionsOfAssets([asset], walletAddress).listen(
-      _onTransactionsUpdated,
-    );
+    _subscription = _repository
+        .watchTransactionsOfAssets([asset], walletAddress)
+        .listen(
+          _onTransactionsUpdated,
+        );
   }
 
   final TransactionRepository _repository;
@@ -65,7 +67,7 @@ class TransactionHistoryFilterCubit extends Cubit<TransactionHistoryFilterState>
 
   @override
   Future<void> close() {
-    _subscription?.cancel();
+    unawaited(_subscription?.cancel());
     return super.close();
   }
 }
diff --git a/lib/screens/transaction_history/widgets/transaction_history_row.dart b/lib/screens/transaction_history/widgets/transaction_history_row.dart
index 0051bbdf..5f973609 100644
--- a/lib/screens/transaction_history/widgets/transaction_history_row.dart
+++ b/lib/screens/transaction_history/widgets/transaction_history_row.dart
@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:intl/intl.dart';
@@ -146,9 +148,11 @@ class TransactionHistoryRowView extends StatelessWidget {
                         )
                       : GestureDetector(
                           onTap: () {
-                            context.read<TransactionHistoryReceiptCubit>().generateReceipt(
-                              transaction.txId,
-                              currency: context.read<SettingsBloc>().state.currency,
+                            unawaited(
+                              context.read<TransactionHistoryReceiptCubit>().generateReceipt(
+                                transaction.txId,
+                                currency: context.read<SettingsBloc>().state.currency,
+                              ),
                             );
                           },
                           child: const Icon(
diff --git a/lib/setup/lifecycle_initializer.dart b/lib/setup/lifecycle_initializer.dart
index 1c0f9a0a..a75c436b 100644
--- a/lib/setup/lifecycle_initializer.dart
+++ b/lib/setup/lifecycle_initializer.dart
@@ -46,7 +46,7 @@ class _LifecycleInitializerState extends State<LifecycleInitializer> {
 
   void _onResumed() {
     getIt<PinAuthCubit>().onAppResumed();
-    getIt<BalanceService>().updateBalance(getIt<AppStore>().primaryAddress);
+    unawaited(getIt<BalanceService>().updateBalance(getIt<AppStore>().primaryAddress));
   }
 
   void _onInactive() {}
diff --git a/pubspec.lock b/pubspec.lock
index bf626bd7..999f3f25 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -18,7 +18,7 @@ packages:
     source: hosted
     version: "0.14.0"
   analyzer:
-    dependency: "direct overridden"
+    dependency: "direct dev"
     description:
       name: analyzer
       sha256: de7148ed2fcec579b19f122c1800933dfa028f6d9fd38a152b04b1516cec120b
diff --git a/pubspec.yaml b/pubspec.yaml
index 9877d964..8bbbd3f6 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -86,6 +86,9 @@ dev_dependencies:
     sdk: flutter
 
   alchemist: ^0.14.0
+  # Direct dev dependency so tool/lints/pattern_guard.dart may import it (the
+  # version is pinned by the analyzer override below).
+  analyzer: ^10.0.0
   bloc_test: ^10.0.0
   build_runner: ^2.13.0
   drift_dev: ^2.32.1
diff --git a/test/analysis_options.yaml b/test/analysis_options.yaml
new file mode 100644
index 00000000..177d5d09
--- /dev/null
+++ b/test/analysis_options.yaml
@@ -0,0 +1,17 @@
+# Inherits the repo-root analyzer config (strict casts/inference/raw-types +
+# null/async lints + the hardened gate from PR #663) and relaxes ONLY the
+# `discarded_futures` lint for test code.
+#
+# Rationale: `discarded_futures` flags Future-returning calls in non-`async`
+# functions. In production (`lib/**`) every such site is resolved with an
+# explicit `unawaited(...)`. In tests, fire-and-forget is idiomatic (pumping
+# a widget, kicking a cubit method inside `setUp`/`blocTest` act blocks,
+# `tester.runAsync` callbacks) and wrapping each one adds noise without
+# guarding any production race. `unawaited_futures` (un-awaited futures inside
+# `async` functions) stays active here, so genuinely awaitable calls in async
+# test bodies are still caught.
+include: ../analysis_options.yaml
+
+linter:
+  rules:
+    discarded_futures: false
diff --git a/test/tool/pattern_guard_test.dart b/test/tool/pattern_guard_test.dart
new file mode 100644
index 00000000..9cdfdfa2
--- /dev/null
+++ b/test/tool/pattern_guard_test.dart
@@ -0,0 +1,99 @@
+// Unit test for the high-pattern guard (tool/lints/pattern_guard.dart).
+// Verifies each rule fires on a known-bad snippet, stays silent on a
+// known-good one, and that `// realunit-lint:ignore <rule>` suppresses a hit.
+@TestOn('vm')
+library;
+
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../tool/lints/pattern_guard.dart';
+
+List<String> _rules(String path, String src) =>
+    scanDartSource(path, src).map((f) => f.rule).toList();
+
+void main() {
+  group('hardcoded_swiss_tax_residence', () {
+    test('fires on a boolean literal', () {
+      final hits = _rules('lib/x.dart', '''
+void f() {
+  register(swissTaxResidence: true);
+}
+''');
+      expect(hits, contains('hardcoded_swiss_tax_residence'));
+    });
+
+    test('silent when passed a value', () {
+      final hits = _rules('lib/x.dart', '''
+void f(bool resident) {
+  register(swissTaxResidence: resident);
+}
+''');
+      expect(hits, isNot(contains('hardcoded_swiss_tax_residence')));
+    });
+  });
+
+  group('fixed_index_address_substring', () {
+    test('fires on two constant indices with end >= 6', () {
+      final hits = _rules('lib/x.dart', 'void f(String a) => a.substring(0, 6);');
+      expect(hits, contains('fixed_index_address_substring'));
+    });
+
+    test('silent on a trivial peek (end < 6)', () {
+      final hits = _rules('lib/x.dart', 'void f(String a) => a.substring(0, 1);');
+      expect(hits, isNot(contains('fixed_index_address_substring')));
+    });
+
+    test('silent on a single dynamic index', () {
+      final hits = _rules('lib/x.dart', 'void f(String a) => a.substring(2);');
+      expect(hits, isNot(contains('fixed_index_address_substring')));
+    });
+  });
+
+  group('cross_flow_brokerbot_endpoint', () {
+    test('fires when a sell file calls a buy endpoint', () {
+      final hits = _rules(
+        'lib/screens/sell/cubits/sell_converter_cubit.dart',
+        "void f(s) => s.getBuyPrice('1', c);",
+      );
+      expect(hits, contains('cross_flow_brokerbot_endpoint'));
+    });
+
+    test('fires when a buy file calls a sell endpoint', () {
+      final hits = _rules(
+        'lib/screens/buy/cubits/buy_converter_cubit.dart',
+        "void f(s) => s.getSellPrice('1', c);",
+      );
+      expect(hits, contains('cross_flow_brokerbot_endpoint'));
+    });
+
+    test('silent when a sell file calls a sell endpoint', () {
+      final hits = _rules(
+        'lib/screens/sell/cubits/sell_converter_cubit.dart',
+        "void f(s) => s.getSellPrice('1', c);",
+      );
+      expect(hits, isNot(contains('cross_flow_brokerbot_endpoint')));
+    });
+  });
+
+  group('suppression', () {
+    test('// realunit-lint:ignore on the line above silences the hit', () {
+      final hits = _rules('lib/x.dart', '''
+void f() {
+  // realunit-lint:ignore hardcoded_swiss_tax_residence — test
+  register(swissTaxResidence: true);
+}
+''');
+      expect(hits, isEmpty);
+    });
+
+    test('ignore for a different rule does not silence', () {
+      final hits = _rules('lib/x.dart', '''
+void f() {
+  // realunit-lint:ignore fixed_index_address_substring — wrong rule
+  register(swissTaxResidence: true);
+}
+''');
+      expect(hits, contains('hardcoded_swiss_tax_residence'));
+    });
+  });
+}
diff --git a/tool/lints/pattern_guard.dart b/tool/lints/pattern_guard.dart
new file mode 100644
index 00000000..b72f3224
--- /dev/null
+++ b/tool/lints/pattern_guard.dart
@@ -0,0 +1,175 @@
+// High-pattern guard — a lightweight static check for the three recurring
+// HIGH-severity defect shapes the Big Brother audit (#657) surfaced and that
+// PR #663 named as `custom_lint` follow-ups. `custom_lint` itself cannot be
+// added today: its current release pins `analyzer: ^8`, while this repo
+// overrides `analyzer: ^10` for the strict-inference gate, so the two cannot
+// co-resolve. This guard reaches the same goal with the `analyzer` package the
+// repo already depends on — purely syntactic (`parseFile`, no element model),
+// so it stays fast and version-tolerant.
+//
+// Run:   dart run tool/lints/pattern_guard.dart
+// CI:    the `High-Pattern Guard` job in .github/workflows/pull-request.yaml
+//        fails the build on any non-allowlisted hit.
+//
+// Suppressing a site (use sparingly, always with a reason on the same line or
+// the line directly above):
+//   // realunit-lint:ignore <rule-id> — <reason>
+//
+// Rule ids:
+//   hardcoded_swiss_tax_residence     a `swissTaxResidence:` argument passed a
+//                                     `true`/`false` literal instead of a value
+//                                     derived from the user's actual residence.
+//   fixed_index_address_substring     `.substring(<int>, <int>)` with two
+//                                     constant indices — assumes a fixed string
+//                                     length and throws RangeError on a shorter
+//                                     one (the audit's qr_address_widget crash).
+//   cross_flow_brokerbot_endpoint     a sell-flow file calling a buy-price/-
+//                                     shares brokerbot method (or vice versa).
+
+import 'dart:io';
+
+import 'package:analyzer/dart/analysis/utilities.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/source/line_info.dart';
+
+class Finding {
+  Finding(this.rule, this.path, this.line, this.message);
+  final String rule;
+  final String path;
+  final int line;
+  final String message;
+}
+
+const _buyMethods = {'getBuyPrice', 'getBuyShares'};
+const _sellMethods = {'getSellPrice', 'getSellShares'};
+
+/// Scans a single Dart source for the three high-pattern violations, honouring
+/// `// realunit-lint:ignore <rule-id>` markers. `path` drives the buy/sell flow
+/// heuristic (rule C). Exposed for the unit test in
+/// `test/tool/pattern_guard_test.dart`.
+List<Finding> scanDartSource(String path, String content) {
+  final result = parseString(content: content, path: path, throwIfDiagnostics: false);
+  final visitor = _PatternVisitor(path, result.unit.lineInfo, content.split('\n'));
+  result.unit.accept(visitor);
+  return visitor.findings;
+}
+
+void main() {
+  final root = Directory('lib');
+  if (!root.existsSync()) {
+    stderr.writeln('pattern_guard: run from the repo root (no lib/ here)');
+    exit(2);
+  }
+
+  final findings = <Finding>[];
+  final files = root
+      .listSync(recursive: true)
+      .whereType<File>()
+      .where((f) => f.path.endsWith('.dart'))
+      // Generated code is tool output, not developer code.
+      .where((f) => !f.path.endsWith('.g.dart'))
+      .where((f) => !f.path.startsWith('lib/generated/'))
+      .toList()
+    ..sort((a, b) => a.path.compareTo(b.path));
+
+  for (final file in files) {
+    findings.addAll(scanDartSource(file.path, file.readAsStringSync()));
+  }
+
+  if (findings.isEmpty) {
+    stdout.writeln('pattern_guard: OK — no high-pattern violations in lib/.');
+    return;
+  }
+
+  findings.sort((a, b) {
+    final p = a.path.compareTo(b.path);
+    return p != 0 ? p : a.line.compareTo(b.line);
+  });
+  for (final f in findings) {
+    stdout.writeln('${f.path}:${f.line} • ${f.rule} • ${f.message}');
+  }
+  stderr.writeln('\npattern_guard: ${findings.length} violation(s). '
+      'Fix them, or add `// realunit-lint:ignore <rule-id> — <reason>`.');
+  exit(1);
+}
+
+class _PatternVisitor extends RecursiveAstVisitor<void> {
+  _PatternVisitor(this.path, this.lineInfo, this.lines);
+
+  final String path;
+  final LineInfo lineInfo;
+  final List<String> lines;
+  final List<Finding> findings = [];
+
+  bool get _isSellFile => path.contains('/sell/') || path.contains('/sell_');
+  bool get _isBuyFile =>
+      (path.contains('/buy/') || path.contains('/buy_')) && !_isSellFile;
+
+  int _lineOf(int offset) => lineInfo.getLocation(offset).lineNumber;
+
+  // A hit is suppressed by a `// realunit-lint:ignore <rule-id> — <reason>`
+  // marker on the hit line itself or anywhere in the contiguous block of
+  // comment lines directly above it (multi-line reasons are fine).
+  bool _suppressed(int line, String rule) {
+    bool has(String s) =>
+        s.contains('realunit-lint:ignore') &&
+        (s.contains(rule) || s.contains('realunit-lint:ignore-all'));
+    if (line >= 1 && line <= lines.length && has(lines[line - 1])) return true;
+    var i = line - 1; // index of the line above the hit (0-based: line-2 + 1)
+    while (i >= 1 && lines[i - 1].trimLeft().startsWith('//')) {
+      if (has(lines[i - 1])) return true;
+      i--;
+    }
+    return false;
+  }
+
+  void _report(String rule, int offset, String message) {
+    final line = _lineOf(offset);
+    if (_suppressed(line, rule)) return;
+    findings.add(Finding(rule, path, line, message));
+  }
+
+  @override
+  void visitNamedExpression(NamedExpression node) {
+    if (node.name.label.name == 'swissTaxResidence' &&
+        node.expression is BooleanLiteral) {
+      _report('hardcoded_swiss_tax_residence', node.offset,
+          'swissTaxResidence passed a boolean literal; derive it from the '
+          "user's residence instead of hardcoding.");
+    }
+    super.visitNamedExpression(node);
+  }
+
+  @override
+  void visitMethodInvocation(MethodInvocation node) {
+    final name = node.methodName.name;
+
+    // Rule B: fixed-index address substring — both indices constant AND the
+    // end index is >= 6, i.e. the call assumes a meaningfully long string
+    // (an address/hash/id). A trivial peek like `substring(0, 1)` is below the
+    // threshold and not flagged.
+    if (name == 'substring') {
+      final args = node.argumentList.arguments;
+      if (args.length >= 2 &&
+          args[0] is IntegerLiteral &&
+          args[1] is IntegerLiteral &&
+          ((args[1] as IntegerLiteral).value ?? 0) >= 6) {
+        _report('fixed_index_address_substring', node.methodName.offset,
+            'substring() with two constant indices assumes a fixed length; '
+            'guard the length or compute indices to avoid RangeError.');
+      }
+    }
+
+    // Rule C: cross-flow brokerbot endpoint.
+    if (_isSellFile && _buyMethods.contains(name)) {
+      _report('cross_flow_brokerbot_endpoint', node.methodName.offset,
+          'sell-flow file calls $name (a buy-side brokerbot endpoint).');
+    } else if (_isBuyFile && _sellMethods.contains(name)) {
+      _report('cross_flow_brokerbot_endpoint', node.methodName.offset,
+          'buy-flow file calls $name (a sell-side brokerbot endpoint).');
+    }
+
+    super.visitMethodInvocation(node);
+  }
+}