Fix mobile-only filter toggle specificity on desktop and add Reset Filters button

public/index.html

@@ -141,6 +141,9 @@
         <option value="updated">Sort: Recently Updated</option>
         <option value="newest">Sort: Newest First</option>
       </select>
+      <button type="button" id="btn-clear-filters" class="btn btn-ghost btn-sm hidden" title="Clear active filters">
+        ✕ Reset
+      </button>
     </div>
   </nav>