close other add forms when opening a new one

introduce closeAllAddForms which strips every add-child and
bulk-add input/button from the tree, and call it at the start of
toggleAddForm and toggleBulkAddForm (after the same-li toggle-off
short-circuit, so clicking the same trigger still closes its own
form). enforces a single open add form across the whole tree.

public/js/text.js

@@ -101,6 +101,21 @@ function renderTree(nodes, textId, depth = 0) {
     return ul;
 }
 
+function closeAllAddForms() {
+    const selectors = [
+        'input.child-title',
+        'button.save-child',
+        'input.bulk-title',
+        'input.bulk-count',
+        'button.save-bulk',
+    ];
+    selectors.forEach((selector) => {
+        document
+            .querySelectorAll('#text-detail ' + selector)
+            .forEach((element) => element.remove());
+    });
+}
+
 function toggleAddForm(li, parentNodeId, textId) {
     const existing = li.querySelector('input.child-title');
     if (existing) {
@@ -109,6 +124,8 @@ function toggleAddForm(li, parentNodeId, textId) {
         return;
     }
 
+    closeAllAddForms();
+
     const input = document.createElement('input');
     input.type = 'text';
     input.className = 'child-title';
@@ -158,6 +175,8 @@ function toggleBulkAddForm(li, parentNodeId, textId) {
         return;
     }
 
+    closeAllAddForms();
+
     const titleInput = document.createElement('input');
     titleInput.type = 'text';
     titleInput.className = 'bulk-title';