add event listener for filter box

layout.html

@@ -285,6 +285,13 @@
 		</template>
 		<script>
 			const init_library = () => {
+				// set up handler for library filtering
+				const filter_box = document.querySelector("#media_library_filter");
+				filter_box.addEventListener("keypress", (e) => {
+					if (e.key === 'Enter') {
+						fetch_filtered_media_items();	
+					}
+				});
 				// set up drag'n'drop file upload handling
 				const upload_target = document.getElementById("upload_target");
 			        upload_target.addEventListener("dragenter", (event) => {