Switch messages area to fixed positioning with centered transform for
better layout stability. Enhance scrollbar appearance with thin style,
improved colors
- Implement singleton pattern for chatApp to prevent multiple instances
- Gate initialization with isInitialized to skip repeated init calls
- Add guards for auth and WebSocket connections to avoid overlaps
- Filter non-message payloads and only render content messages
- Improve scroll-to-bottom button visibility and interaction
- Update scrollbar styling, including dark theme rules
- Removed stray `o` character after `pendingContextChange` declaration to fix a syntax error in `chat.js`.
- Added safety check before calling `focus()` on the message input element.
- Implemented `preloadChatCSS()` to preload chat styles and prevent flash‑of‑unstyled‑content.
- Added GSAP fade‑in animation when switching sections for smoother visual transition.
- Ensured input field is auto‑focused after a section loads.
- Changed the default initial section from `drive` to `chat` to align with new default behavior.
- Removed the unused `serve_html` handler and its import.
- Added a fallback static file service that serves `index.html` for any unmatched path, enabling proper SPA routing.
- Reordered service registration to place the fallback before the explicit index route.
- Cleaned up redundant blank lines and imports in `mod.rs`.
**Client-side (chat.js) updates**
- Renamed the message input variable from `input` to `messageInputEl` for clarity.
- Introduced `pendingContextChange` placeholder for future context handling.
- Switched initialization event from `document 'ready'` to `window 'load'`.
- Updated DOM element assignments and focus calls to use the new variable name.
- Removed unused sidebar auto‑close logic and obsolete session loading functions (`loadSessions`, `loadSessionHistory`).
- Minor refactoring and comment adjustments to improve readability and eliminate dead code.
- Add `*.log` to `.gitignore` to exclude log files from version control.
- Change `auth_handler` to `pub` in `src/auth/mod.rs` to make the endpoint publicly accessible.
- Remove unused `bot_index` import and route; replace direct service registration with `web_server::configure_app` in `src/main.rs`.
- Refactor `src/web_server/mod.rs`:
- Remove the `bot_index` handler.
- Introduce `serve_html` helper for loading HTML pages.
- Simplify static file serving by configuring separate routes for JS and CSS assets.
- Centralize all route and static file configuration in `configure_app`.
- Clean up related imports and improve error handling for missing pages.
- Added a new "Chat" link in the desktop navigation bar with appropriate click handling and active state styling.
- Updated the layout configuration to include the Chat section, mapping it to `chat/chat.html`.
- Enables users to switch to the Chat interface directly from the main navigation.
