Add post-v1 shared-rule drift guard

.github/workflows/shared-rule-drift.yml

@@ -0,0 +1,20 @@
+name: shared-rule-drift
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  compare-shared-rules:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - name: Validate shared-rule synchronization
+        shell: pwsh
+        run: ./scripts/check-shared-rule-drift.ps1

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## Unreleased
+
+Post-v1 maintenance hardening only. No installer behavior change. No intended change to the canonical reusable orientation behavior beyond maintenance markers.
+
+- Add a deterministic shared-rule drift guard for canonical `skills/codebase-orient/SKILL.md` vs the bootstrap embedded shared-rule snapshot in `skills/install-codebase-orient/SKILL.md`, including explicit shared-block markers, a validation script, and a GitHub Actions check that now guards those shared blocks against future accidental drift.
+- Align the bootstrap embedded shared-rule snapshot to canonical wording so future bootstrap-generated project-local skills receive the synchronized shared-rule content.
+- Freeze the former `docs/V1_RELEASE_PLAN.md` contents as `docs/releases/v1.0-validation-record.md` and keep `docs/V1_RELEASE_PLAN.md` as a short compatibility pointer now that `v1.0.0` has shipped.
+
 ## 1.0.0 - 2026-05-24
 
 First stable public release of `codebase-orient`.

README.md

@@ -299,7 +299,7 @@ If you install a project-local skill and want to track only the shared skill fil
 - [`skills/codebase-orient/SKILL.md`](skills/codebase-orient/SKILL.md): canonical reusable skill behavior
 - [`skills/install-codebase-orient/SKILL.md`](skills/install-codebase-orient/SKILL.md): Claude Code bootstrap skill behavior and versioned embedded template
 - [`CHANGELOG.md`](CHANGELOG.md): release history
-- [`docs/V1_RELEASE_PLAN.md`](docs/V1_RELEASE_PLAN.md): release criteria, validation record, and current known gaps
+- [`docs/releases/v1.0-validation-record.md`](docs/releases/v1.0-validation-record.md): frozen historical validation record for `v1.0.0`
 - [`scripts/`](scripts/): install and validation helpers
 
 Tracked repo-maintenance text in this repo follows an ASCII punctuation convention. The check scripts are:
@@ -312,6 +312,12 @@ Tracked repo-maintenance text in this repo follows an ASCII punctuation conventi
 ./scripts/check-ascii-punctuation.sh
 ```
 
+Shared canonical/bootstrap rule blocks can also be validated directly with:
+
+```powershell
+.\scripts\check-shared-rule-drift.ps1
+```
+
 <details>
 <summary>Uninstall reference</summary>