- Add optimistic update + rollback to archive mutation
- Replace Trash2 with Archive icon (correct semantics)
- Add Tooltip on archive button, replace native title
- Show spinner during archive, toast on error
- Use cn() for className composition
- Align chat window offset to bottom-2 right-2 (match FAB)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move chat queries, mutations, and store from apps/web/core/chat/ and
apps/web/features/chat/store.ts to packages/core/chat/. Refactor store
to use createChatStore({ storage }) factory pattern (mirrors auth store)
so it works in both web (localStorage) and desktop (Electron) without
direct browser API access. Register chat store in CoreProvider.initCore.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
