feat(cli): TUI component architecture — status bars, message list, input bar

- Split monolithic app.tsx into composable components:
  - TopBar: connection indicator (●/○), gateway URL, model name, conversation ID
  - BottomBar: cwd, git branch, token usage
  - MessageList: timestamped messages, tool call indicators, thinking display
  - InputBar: context-aware prompt with streaming/disconnect states
- Extract socket logic into useSocket hook with typed events
- Extract git/cwd info into useGitInfo hook
- Quiet disconnect: single indicator instead of error flood
- Add @mosaic/types dependency for typed Socket.IO events
- Add PRD and task tracking docs

Tasks: TUI-001 through TUI-007 (Wave 1)

pnpm-lock.yaml

@@ -286,6 +286,9 @@ importers:
       '@mosaic/quality-rails':
         specifier: workspace:^
         version: link:../quality-rails
+      '@mosaic/types':
+        specifier: workspace:^
+        version: link:../types
       commander:
         specifier: ^13.0.0
         version: 13.1.0