Add separate MobileTitleBar component for mobile layout

- Create MobileTitleBar component with fixed top position
- Split title bar from tabs bar on mobile (title always on top)
- Add data-has-actions attribute for action button detection
- Track --tab-pill-height CSS variable for tab buttons
- Remove extra padding from mobile content padding-top
- Hide tabs container when no tabs or actions present

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/pages/admin/Sources.tsx

@@ -1,6 +1,7 @@
 import { useAuth } from '../../contexts/AuthContext';
 import { useTranslation } from '../../contexts/LanguageContext';
 import { useSidebar } from '../../contexts/SidebarContext';
+import MobileTitleBar from '../../components/MobileTitleBar';
 import TabsScroller from '../../components/TabsScroller';
 import { SwipeableContent } from '../../components/SwipeableContent';
 import '../../styles/AdminPanel.css';
@@ -16,11 +17,14 @@ export default function Sources() {
 
     return (
         <SwipeableContent className="main-content admin-panel-root">
+            <MobileTitleBar
+                title={t.sourcesPage.title}
+                menuLabel={t.theme.toggleMenu}
+                onMenuClick={toggleMobileMenu}
+                variant="admin"
+            />
             <div className="admin-tabs-container">
                 <TabsScroller className="admin-tabs-slider">
-                    <button className="mobile-menu-btn" onClick={toggleMobileMenu} aria-label={t.theme.toggleMenu}>
-                        <span className="material-symbols-outlined">menu</span>
-                    </button>
                     <div className="admin-title-section">
                         <span className="admin-title-text">{t.sourcesPage.title}</span>
                     </div>