Frontend optimizations: SVG icons, remove updateFileIcons, unify rendering, scope translatePage

- Replace Font Awesome CDN with inline SVG system (icons.js + MutationObserver)
- Remove updateFileIcons() (~140 lines) - redundant with backend icon_class + MutationObserver
- Migrate favorites.js and recent.js to use shared ui.renderFolders/renderFiles (eliminate ~260 lines of duplicate rendering + per-item event listeners)
- Add view-mode aware click delegation for favorites/recent views
- Fix _createFileCard to apply icon_special_class
- Add translateElement(root) for scoped i18n translation
- Replace full-page translatePage() calls with scoped translateElement() or inline t()
- Remove redundant translatePage() calls in shared.js and auth.js
- Remove Alpine.js from Service Worker cache

static/js/auth.js

@@ -286,10 +286,7 @@ function initLanguageSelector() {
             await configureOidcLoginUI();
         }
         
-        // Translate the page with new locale
-        if (window.i18n && window.i18n.translatePage) {
-            window.i18n.translatePage();
-        }
+        // setLocale() already calls translatePage() internally
     });
 }