- Add search/filter input to sidebar that filters conversations by title
- Add rename via double-click or context menu (right-click), confirmed with Enter or blur
- Add delete with inline confirmation dialog in context menu
- Add archive/unarchive via context menu with collapsible archived section
- Add auto-title: generates conversation title from first message content
- Show relative timestamps (e.g. "2h ago", "Yesterday") instead of raw dates
- Extend Conversation type with `archived` boolean field
- Add `archived` column + index to conversations DB schema (migration 0001)
- Extend UpdateConversationDto with optional `archived` field
Fixes#121
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
