Add favicon route and minor cleanup

- Add /favicon.ico route (204) to avoid browser 404
- CSS formatting tweaks
- Pipfile trailing newline

Co-authored-by: Cursor <cursoragent@cursor.com>

run_web.py

@@ -128,6 +128,11 @@ async def run_local():
         """Serve the settings page."""
         return send_file('src/templates/settings.html')
     
+    # Favicon: avoid 404 in browser console (no file needed)
+    @app.route('/favicon.ico')
+    def favicon(request):
+        return '', 204
+    
     # Static file route
     @app.route("/static/<path:path>")
     def static_handler(request, path):