## Summary
- record server divergence when an assistant changes a notebook with
local unsaved edits
- clear the session-only marker after a successful save or notebook
removal
- cover update, delete, saved eviction, and lifecycle behavior
## Verification
- pnpm --dir apps/studio exec vitest run
state/notebooks/notebooks-state.test.ts
lib/ai/notebook-cache-invalidation.test.ts
- pnpm --dir apps/studio exec eslint state/notebooks/notebooks-state.ts
state/notebooks/notebooks-state.test.ts
lib/ai/notebook-cache-invalidation.ts
lib/ai/notebook-cache-invalidation.test.ts
- pnpm --dir apps/studio typecheck
Stacked on the approval-warning PR for FE-4255.
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Bug Fixes**
* Improved handling of server changes to notebooks with unsaved local
edits.
* Server updates and deletions are now tracked as divergences instead of
being silently skipped.
* Divergence indicators are cleared when changes are saved or notebooks
are removed.
* Unrelated notebook changes no longer create false conflicts.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->