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/css/components/uploadDropdown.css

@@ -0,0 +1,97 @@
+/* Upload Dropdown */
+.upload-dropdown {
+	position: relative;
+	display: inline-block;
+}
+
+.upload-dropdown .btn-primary {
+	display: flex;
+	align-items: center;
+	gap: 6px;
+}
+
+.upload-dropdown-menu {
+	display: none;
+	position: absolute;
+	top: calc(100% + 6px);
+	left: 0;
+	min-width: 200px;
+	background: white;
+	border-radius: 12px;
+	box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
+	border: 1px solid #e2e8f0;
+	z-index: 1000;
+	overflow: hidden;
+	animation: dropdownFadeIn 0.15s ease-out;
+}
+
+.upload-dropdown-menu.show {
+	display: block;
+}
+
+@keyframes dropdownFadeIn {
+	from {
+		opacity: 0;
+		transform: translateY(-8px);
+	}
+	to {
+		opacity: 1;
+		transform: translateY(0);
+	}
+}
+
+.upload-dropdown-item {
+	display: flex;
+	align-items: center;
+	gap: 12px;
+	width: 100%;
+	padding: 12px 16px;
+	border: none;
+	background: none;
+	color: #334155;
+	font-size: 14px;
+	cursor: pointer;
+	transition: background 0.15s ease;
+	text-align: left;
+}
+
+.upload-dropdown-item:hover {
+	background: #f1f5f9;
+}
+
+.upload-dropdown-item:active {
+	background: #e2e8f0;
+}
+
+.upload-dropdown-item i {
+	width: 20px;
+	text-align: center;
+	color: #64748b;
+	font-size: 15px;
+}
+
+.upload-dropdown-item:first-child {
+	border-bottom: 1px solid #f1f5f9;
+}
+
+[data-theme="dark"] .upload-dropdown-menu {
+	background: #1e293b;
+	border-color: #334155;
+	box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
+}
+
+[data-theme="dark"] .upload-dropdown-item {
+	color: #cbd5e1;
+}
+
+[data-theme="dark"] .upload-dropdown-item:hover {
+	background: #334155;
+}
+
+[data-theme="dark"] .upload-dropdown-item:active {
+	background: #475569;
+}
+
+[data-theme="dark"] .upload-dropdown-item i {
+	color: #94a3b8;
+}