feat: implement full breadcrumb path navigation in Files tab

- Add breadcrumbPath array to app state for tracking folder hierarchy
- Rewrite updateBreadcrumb() to render full path: Home > folder > subfolder
- Each breadcrumb segment is clickable to navigate back to that level
- Current folder shown in bold (non-clickable), parent folders as links
- Reset breadcrumb path on tab switch, home navigation, and initial load
- Update navigateFolder/selectFolder to push to breadcrumb path
- Enhanced breadcrumb CSS with hover effects and dark mode support

static/index.html

@@ -8,10 +8,12 @@
     <script>if(localStorage.getItem('oxicloud_theme')==='dark')document.documentElement.setAttribute('data-theme','dark');</script>
     
     <!-- Styles -->
-    <link rel="stylesheet" href="/css/style.css">
-    <link rel="stylesheet" href="/css/inlineViewer.css">
-    <link rel="stylesheet" href="/css/favorites.css">
-    <link rel="stylesheet" href="/css/recent.css">
+    <link rel="stylesheet" href="/css/main.css">
+    <link rel="stylesheet" href="/css/views/inlineViewer.css">
+    <link rel="stylesheet" href="/css/views/favorites.css">
+    <link rel="stylesheet" href="/css/views/recent.css">
+    <link rel="stylesheet" href="/css/views/shared.css">
+    <link rel="stylesheet" href="/css/views/trash.css">
 
     <!-- Scripts (defer: download in parallel, execute in order, after HTML parsed) -->
     <script defer src="/js/core/i18n.js"></script>