refactor: Phase 5 - Remove manual cache invalidations (#707)

* chore, cleanup leftovers of tanstack refactoring

* refactor: Complete Phase 5 - Remove manual cache invalidations

- Removed all manual cache invalidations from knowledge queries
- Updated task queries to rely on backend consistency
- Fixed optimistic update utilities to handle edge cases
- Cleaned up unused imports and test utilities
- Fixed minor TypeScript issues in UI components

Backend now ensures data consistency through proper transaction handling,
eliminating the need for frontend cache coordination.


* docs: Enhance TODO comment for knowledge optimistic update issue

- Added comprehensive explanation of the query key mismatch issue
- Documented current behavior and impact on user experience
- Listed potential solutions with tradeoffs
- Created detailed PRP story in PRPs/local/ for future implementation
- References specific line numbers and implementation details

This documents a known limitation where optimistic updates to knowledge
items are invisible because mutations update the wrong query cache.

.gitignore

@@ -10,3 +10,5 @@ PRPs/stories/
 tmp/
 temp/
 UAT/
+
+.DS_Store