feat: implement stub composables + wire VersionPreviewModal to useVersionRestore

[leotrs]

Summary

• Implemented useAwareness, useEditor, useYText, and useCurrentUser composables — previously stubs that threw errors, now real inject-based implementations
• Provided readOnlyCompartment from Canvas.vue → EditorCodeMirror.vue so useEditor can toggle read-only via the same Compartment
• Wired VersionPreviewModal.vue to call useVersionRestore().restoreVersion() instead of raw window.__cmView.dispatch(), gaining concurrent editor detection, read-only locking, awareness broadcasting, and atomic Y.js transactions

Test plan

• 26 unit tests pass (useAwareness, useEditor, useYText, useCurrentUser, useVersionRestore)
• E2E: version restore flow (owner restores version, content replaced via Y.js)
• E2E: concurrent editor detection shows confirm dialog
• E2E: read-only lock during restore

🤖 Generated with Claude Code

[netlify]

✅ Deploy Preview for rsm-studio-frontend canceled.

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[netlify]

✅ Deploy Preview for rsm-studio-site canceled.

Name	Link
🔨 Latest commit	61c1c9f
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[leotrs]

Needs human review

What changed: Version restore now goes through useVersionRestore composable instead of raw window.__cmView.dispatch(), adding concurrent editor detection (confirm dialog), read-only editor locking during restore, and Y.js awareness broadcasting.

Review checklist:

1. Open the deploy preview: https://deploy-preview-368--rsm-studio-frontend.netlify.app
2. Open a file in the editor as the owner
3. Click version history and select a previous version to preview
4. Verify the restore button appears and clicking it shows the confirmation step
5. Confirm the restore and verify content is replaced correctly
6. Test cancelling the restore — editor content should remain unchanged
7. If possible, open the same file in two browser tabs to test concurrent editor detection: the second tab should trigger a confirm dialog warning about other active editors

What to look for:

• Restore completes without errors and editor content matches the restored version
• Editor is briefly read-only during restore (no typing possible)
• Cancelling restore at any step leaves the document untouched
• Error states (e.g., network failure during restore) show an alert and don't leave the editor locked in read-only
• No regressions in normal editing flow after a restore completes

[leotrs]

Needs human review

What changed: Version restore now goes through useVersionRestore composable instead of raw window.__cmView.dispatch(), adding concurrent editor detection (confirm dialog), read-only editor locking during restore, and Y.js awareness broadcasting.

Review checklist:

1. Open the deploy preview: https://deploy-preview-368--rsm-studio-frontend.netlify.app
2. Log in as the file owner and open a document with version history
3. Open the version preview modal and click "Restore"
4. Verify the confirmation flow works (click Restore → see confirmation → confirm or cancel)
5. After confirming, verify the document content is replaced with the restored version
6. Test cancelling the restore — content should remain unchanged
7. If possible, open the same document in two browser tabs to test concurrent editor detection: the restoring user should see a confirm dialog naming the other active user(s)

What to look for:

• Restore button shows correct version number
• Confirmation dialog appears before restore executes
• Content is correctly replaced after restore (no partial content, no duplicates)
• Modal closes properly after successful restore
• Error alert appears if restore fails (e.g., simulate by disconnecting network)
• No regressions in the version preview display (content loads, loading/error states work)
• If testing with two tabs: concurrent editor warning names the other user correctly

[github-actions]

Preview Deploy

Frontend: https://pr-368--rsm-studio-frontend.netlify.app
Backend: https://aris-backend-staging.fly.dev (staging)
API docs: https://aris-backend-staging.fly.dev/docs

Test user: preview-pr-368@aris.pub

This preview will be destroyed when the PR is closed.

[leotrs]

Needs human review

What changed: Version restore now goes through Y.js transactions via useVersionRestore composable instead of raw window.__cmView.dispatch(), adding concurrent editor detection (confirm dialog), read-only editor locking during restore, and awareness broadcasting.

Review checklist:

1. Open two browser tabs logged in as different users on the same file
2. In Tab A, open the version history panel and select a previous version to preview
3. Verify the version preview modal loads content correctly
4. With Tab B's cursor active in the editor, click "Restore" in Tab A
5. Verify a confirmation dialog appears warning about concurrent editors (Tab B)
6. Click "Cancel" — verify nothing changes in the editor
7. Click "Restore" again, then "Confirm" — verify:
   • The editor briefly becomes read-only during restore
   • Content is replaced via Y.js (Tab B sees the change in real-time)
   • The "restored" event fires and modal closes properly
8. Test restoring with no other editors present — confirm dialog should NOT appear
9. Test restore when editor is not initialized (e.g., navigate away mid-restore) — should show error gracefully

What to look for:

• Confirm dialog text is clear and mentions the other user(s) by name
• Editor unlocks after restore completes (not stuck in read-only)
• Editor unlocks even if restore fails (error path)
• No content duplication or loss during Y.js transaction
• Awareness state clears after restore (no stale "restoring" indicator)