fix: prevent sidebar wheel from blocking tree library scrolling

frontend/src/pages/TreeLibraryPage.tsx

@@ -248,10 +248,8 @@ export function TreeLibraryPage() {
     selectedCategoryId || selectedTags.length > 0 || searchQuery || selectedFolderId
 
   return (
-    <div className="flex h-full">
-      {/* Main Content */}
-      <div className="flex-1 overflow-auto">
-        <div className="container mx-auto px-4 py-6 sm:px-6 sm:py-8">
+    <div className="min-h-full">
+      <div className="container mx-auto px-4 py-6 sm:px-6 sm:py-8">
           <div className="mb-6 flex flex-col gap-4 sm:mb-8 sm:flex-row sm:items-start sm:justify-between">
             <div>
               <h1 className="text-2xl font-bold font-heading text-foreground sm:text-3xl">
@@ -520,7 +518,6 @@ export function TreeLibraryPage() {
               )}
             </>
           )}
-        </div>
       </div>
 
       {/* Folder Edit Modal */}