Add User Preferences to MVP, add Phase 2.5 Personal Branching specs

- Fixed minor typescript errors that would show during compile

frontend/src/pages/TreeLibraryPage.tsx

@@ -95,6 +95,7 @@ export function TreeLibraryPage() {
         <select
           value={selectedCategory}
           onChange={(e) => setSelectedCategory(e.target.value)}
+          aria-label="Filter by category"
           className={cn(
             'rounded-md border border-input bg-background px-3 py-2',
             'text-foreground focus:border-primary focus:outline-none focus:ring-1 focus:ring-primary'