Add app bars, toolbars, tabs and the account and theme controls

M3 Expressive top app bars (small, centered, medium and large flexible,
search) that collapse with CSS sticky, docked and floating toolbars,
primary and secondary tabs with a view-transition indicator, section
navigation, the account menu and theme toggles.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V9NnLxnPp8vaaurb3Z1MFy

resources/css/material.css

@@ -26,6 +26,9 @@
 @import './components/menu.css';
 @import './components/selection.css';
 @import './components/search.css';
+@import './components/tabs.css';
+@import './components/app-bar.css';
+@import './components/toolbar.css';
 
 @layer base {
     html {