fix(ios): stop reading the pasteboard in text input canPerformAction

[huhuanming]

Summary

Fixes an iOS 27 main-thread hang in @onekeyfe/react-native-text-input that the watchdog turns into a kill (Sentry REACT-NATIVE-4Y1, "Fatal App Hang Fully Blocked", iPhone17,1 / iOS 27.0 24A437, app 6.6.0 build 2026091844).

Same change as #131 (which targets hotfix/3.0.154 for app-monorepo release/v6.6.0), applied to main so the next regular release carries it.

Root cause

The RCTUITextField(OneKeyPaste) / RCTUITextView(OneKeyPaste) swizzle of canPerformAction:withSender: read UIPasteboard.generalPasteboard.hasImages, which is a synchronous XPC call to pasteboardd. On iOS 27, UIIntelligenceSupport validates UICommands from a run-loop block with no user action, so this runs on the main thread in the background:

UIIntelligenceSupport (CFRunLoop block)
  -[UICommand _resolvedTargetFromFirstTarget:sender:]
    _UIResponderCanPerformAction
      -[RCTUITextField(OneKeyPaste) onekey_canPerformAction:withSender:]
        +[_UIConcretePasteboard _pasteboardNamed:createIfNotFound:]
          -[PBServerConnection pasteboardWithName:...]
            xpc_connection_send_message_with_reply_sync   <- blocked >= 5 s

Fix

• onekey_canPerformAction: reads a cached std::atomic<bool> instead of touching UIPasteboard.
• A serial background queue refreshes the cache on UIPasteboardChangedNotification, UIApplicationDidBecomeActiveNotification, and text field / text view begin-editing. Refresh requests that arrive while one is queued are merged into it.
• The paste path (onekey_paste:) is unchanged; it still reads the pasteboard only when the user actually pastes.

Tradeoff: right after returning from another app with a copied image, the Paste menu item may miss the image for the moment the async refresh takes. Text paste is unaffected (it falls through to UIKit).

Test plan

• clang++ -fsyntax-only against the iOS 27.0 SDK and the app's React headers: no errors or warnings
• iOS 27 device: long-press a text input with an image on the pasteboard, then Paste works and the image paste event fires
• iOS 27 device: copy an image in Photos, return to the app, then paste into a text input
• iOS 26 device: text and image paste unchanged

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