Merge toolbar-fixes.css and user-theme.css into globals.css

Consolidate two override CSS files into globals.css to reduce the number
of separate stylesheets. Both files were primarily overriding rules
already in globals.css (81% and 55% overlap respectively).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/layout.tsx

@@ -8,8 +8,6 @@ import "./favorites-widget.css";
 import "./admin.css";
 import "./note-widget.css";
 import "./calendar-scale.css";
-import "./toolbar-fixes.css";
-import "./user-theme.css";
 import "./widget-density.css";
 import "./clock-widget.css";
 import "./search-widget.css";