Hide visibility filter for anonymous users on home page

Anonymous users can only see public projects, so the visibility
filter dropdown is not useful for them. Only show it when logged in.

frontend/src/pages/Home.tsx

@@ -179,6 +179,7 @@ function Home() {
         </form>
       )}
 
+      {user && (
         <div className="list-controls">
           <FilterDropdown
             label="Visibility"
@@ -187,8 +188,9 @@ function Home() {
             onChange={handleVisibilityChange}
           />
         </div>
+      )}
 
-      {hasActiveFilters && (
+      {user && hasActiveFilters && (
         <FilterChipGroup onClearAll={clearFilters}>
           {visibility && (
             <FilterChip