- Add fallback favicon using Google's favicon service (s2/favicons API)
- If both tab.favIconUrl and Google service fail, gracefully hide broken image
- Enhance navigation message styling for better visibility:
- Use accent colors (bg-accent/50 with border-accent) instead of muted secondary
- Increase padding (px-3 py-2) and add vertical margin (my-2)
- Add shadow-sm for subtle depth
- Make title font-medium for better contrast
- Use border-2 instead of border for more prominence
- Add ?new=true query param to prevent auto-loading latest session
- Style navigation message as clickable badge with background
- Add cursor-pointer, truncate, and max-width for proper text overflow
- Click navigation message to open page in new tab
- Show URL on hover
- Add onBeforeSend callback to ChatPanel and AgentInterface
- Add onBeforeToolCall callback (for future permission dialogs)
- Create NavigationMessage custom message type
- Add browserMessageTransformer that converts nav messages to <system> tags
- Track last submitted URL and tab index
- Auto-insert navigation message when URL/tab changes on user submit
- Navigation message shows favicon + page title in UI
- LLM receives: <system>Navigated to [title] (tab X): [url]</system>
