submit bulk add form on enter key

extract the save-bulk handler into a submit closure shared by the
save button click and a keydown listener on both the title and
count inputs. focus the title input as soon as the form opens.

public/js/text.js

@@ -172,7 +172,8 @@ function toggleBulkAddForm(li, parentNodeId, textId) {
     const saveBtn = document.createElement('button');
     saveBtn.textContent = 'Save';
     saveBtn.className = 'save-bulk';
-    saveBtn.addEventListener('click', () => {
+
+    function submit() {
         const titlePrefix = titleInput.value.trim();
         const count = parseInt(countInput.value);
         if (!titlePrefix || !count || count < 1) return;
@@ -189,9 +190,21 @@ function toggleBulkAddForm(li, parentNodeId, textId) {
                 return res.json();
             })
             .then(() => fetchAndRenderNodes(textId));
-    });
+    }
+
+    function submitOnEnter(event) {
+        if (event.key === 'Enter') {
+            event.preventDefault();
+            submit();
+        }
+    }
+
+    saveBtn.addEventListener('click', submit);
+    titleInput.addEventListener('keydown', submitOnEnter);
+    countInput.addEventListener('keydown', submitOnEnter);
 
     li.appendChild(titleInput);
     li.appendChild(countInput);
     li.appendChild(saveBtn);
+    titleInput.focus();
 }