Fix TypeScript build errors

- Remove unused variables (allFolders, getFolderDepth, hasChildren, legacyCategories)
- Fix Lucide icon title prop by wrapping in span elements

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

frontend/src/components/library/AddToFolderMenu.tsx

@@ -38,10 +38,7 @@ export function AddToFolderMenu({ treeId, onFolderCreated }: AddToFolderMenuProp
   const loadFoldersAndAssignments = async () => {
     setIsLoading(true)
     try {
-      const [foldersData, allFolders] = await Promise.all([
-        foldersApi.list(),
-        Promise.resolve([]), // Will load tree's folder assignments below
-      ])
+      const foldersData = await foldersApi.list()
       setFolders(foldersData)
 
       // Check which folders contain this tree

frontend/src/components/library/FolderSidebar.tsx

@@ -46,18 +46,6 @@ function buildFolderTree(folders: FolderListItem[]): FolderTreeItem[] {
   return rootFolders
 }
 
-// Calculate folder depth (for limiting nesting)
-function getFolderDepth(folders: FolderListItem[], folderId: string): number {
-  const folder = folders.find((f) => f.id === folderId)
-  if (!folder || !folder.parent_id) return 1
-  return 1 + getFolderDepth(folders, folder.parent_id)
-}
-
-// Check if folder has children
-function hasChildren(folders: FolderListItem[], folderId: string): boolean {
-  return folders.some((f) => f.parent_id === folderId)
-}
-
 // Get all descendant IDs (for cascade delete warning)
 function getDescendantIds(folders: FolderListItem[], folderId: string): string[] {
   const children = folders.filter((f) => f.parent_id === folderId)

frontend/src/components/tree-editor/TreeMetadataForm.tsx

@@ -24,7 +24,6 @@ export function TreeMetadataForm() {
   } = useTreeEditorStore()
 
   const [categories, setCategories] = useState<CategoryListItem[]>([])
-  const [legacyCategories, setLegacyCategories] = useState<string[]>([])
   const [customCategory, setCustomCategory] = useState(false)
 
   // Load categories

frontend/src/pages/TreeLibraryPage.tsx

@@ -274,9 +274,13 @@ export function TreeLibraryPage() {
                     <h3 className="font-semibold text-card-foreground">{tree.name}</h3>
                     <div className="flex items-center gap-2">
                       {tree.is_public ? (
-                        <Globe className="h-4 w-4 text-muted-foreground" title="Public tree" />
+                        <span title="Public tree">
+                          <Globe className="h-4 w-4 text-muted-foreground" />
+                        </span>
                       ) : (
-                        <Lock className="h-4 w-4 text-muted-foreground" title="Private tree" />
+                        <span title="Private tree">
+                          <Lock className="h-4 w-4 text-muted-foreground" />
+                        </span>
                       )}
                       {tree.category_info && (
                         <span className="rounded-full bg-secondary px-2 py-0.5 text-xs text-secondary-foreground">