- Add renderMarkdownPreview() function to app.js matching server-side Go implementation
- Support headers (#, ##, ###), bold (**text**), italic (*text*), code (`code`), code blocks (```lang), lists (* item), and @mentions
- Add Edit/Preview tab UI above chat textarea with active tab highlighting
- Preview updates in real-time with 300ms debounce while typing
- Respect user's markdown_preview_default preference from settings (edit or preview)
- Pass user preferences to chat template via ChatHandler
- Add markdown tab and preview container styles matching beige/blue/pink theme
- Preview shows formatted HTML identical to actual chat messages
- Support dark mode with appropriate color adjustments for tabs and preview
- Tabs use cyan accent for active state, orange for inactive hover
User can switch between editing markdown and seeing live preview of formatted output.
Features added:
- Connection status indicator (green=connected, yellow=connecting, red=disconnected)
- Exponential backoff reconnection (1s → 2s → 4s → ... → 30s max)
- Typing indicators showing who is typing (up to 3 users, with overflow count)
- Message status (⋯ sending, ✓ sent, ✗ failed with retry option)
- Jump-to-bottom button with unread message count badge
- Smart scroll preservation (stays in place unless already at bottom)
- Optimistic UI for sent messages (appears immediately, updates with real status)
- Backend support for broadcasting typing events to other users