fix(ui): suppress "No suggestions" popup while typing in strings

- Disable quickSuggestions for strings (was triggering on every keystroke)
- Only auto-trigger suggestions on explicit cursor navigation (click/arrows),
  not on typing (CursorChangeReason.Explicit only)
- Code actions now replace full document for clean undo + proper formatting

Author: lan17

ui/src/core/page-components/agent-detail/modals/edit-control/json-editor-language.ts

@@ -1859,9 +1859,12 @@ function buildNodeTransformAction(
   title: string,
   transform: (parsed: unknown) => unknown
 ): import('monaco-editor').languages.CodeAction | null {
-  const nodeText = model
-    .getValue()
-    .substring(node.offset, node.offset + node.length);
+  // Parse the full document, apply the transform to the target node,
+  // then re-serialize the whole document. This produces a single edit
+  // that replaces the entire content with properly formatted JSON,
+  // making undo a clean single-step revert.
+  const fullText = model.getValue();
+  const nodeText = fullText.substring(node.offset, node.offset + node.length);
   let parsed: unknown;
   try {
     parsed = JSON.parse(nodeText);
@@ -1872,9 +1875,25 @@ function buildNodeTransformAction(
   const result = transform(parsed);
   if (result === undefined) return null;
 
-  const newText = JSON.stringify(result, null, 2);
-  const startPos = model.getPositionAt(node.offset);
-  const endPos = model.getPositionAt(node.offset + node.length);
+  // Rebuild full document with the transformed node
+  const newNodeText = JSON.stringify(result);
+  const rawDoc =
+    fullText.substring(0, node.offset) +
+    newNodeText +
+    fullText.substring(node.offset + node.length);
+
+  let newText: string;
+  try {
+    newText = JSON.stringify(JSON.parse(rawDoc), null, 2);
+  } catch {
+    // Fallback: just replace the node
+    newText =
+      fullText.substring(0, node.offset) +
+      JSON.stringify(result, null, 2) +
+      fullText.substring(node.offset + node.length);
+  }
+
+  const fullRange = model.getFullModelRange();
 
   return {
     title,
@@ -1885,10 +1904,10 @@ function buildNodeTransformAction(
           resource: model.uri,
           textEdit: {
             range: new monaco.Range(
-              startPos.lineNumber,
-              startPos.column,
-              endPos.lineNumber,
-              endPos.column
+              fullRange.startLineNumber,
+              fullRange.startColumn,
+              fullRange.endLineNumber,
+              fullRange.endColumn
             ),
             text: newText,
           },

ui/src/core/page-components/agent-detail/modals/edit-control/json-editor-view.tsx

@@ -74,7 +74,7 @@ if (typeof document !== 'undefined') {
 const EDITOR_OPTIONS: import('monaco-editor').editor.IStandaloneEditorConstructionOptions =
   {
     automaticLayout: true,
-    quickSuggestions: { other: true, strings: true, comments: false },
+    quickSuggestions: { other: true, strings: false, comments: false },
     suggestOnTriggerCharacters: true,
     wordBasedSuggestions: 'off',
     suggest: {
@@ -366,26 +366,9 @@ export const JsonEditorView = ({
 
       const text = editor.getValue();
 
-      // Deferred reformat for multi-line edits (e.g., code actions like "Wrap in AND").
-      // Must use queueMicrotask — editing inside onDidChangeModelContent crashes Monaco.
-      const isMultiLineEdit =
-        !e.isUndoing &&
-        !e.isRedoing &&
-        e.changes.length === 1 &&
-        (e.changes[0].text.includes('\n') ||
-          e.changes[0].range.endLineNumber >
-            e.changes[0].range.startLineNumber);
-      if (isMultiLineEdit) {
-        queueMicrotask(() => {
-          const current = editor.getValue();
-          const formatted = tryFormat(current);
-          if (formatted && formatted !== current) {
-            isProgrammaticEdit = true;
-            replaceAllContent(editor, formatted, 'auto-reformat');
-            handleJsonChange(formatted);
-          }
-        });
-      }
+      // No auto-reformat here — code actions produce formatted JSON by replacing
+      // the full document (see buildNodeTransformAction). Auto-reformatting would
+      // create a second undo entry that breaks Ctrl+Z.
 
       // Debounced hints
       if (hintTimer) window.clearTimeout(hintTimer);
@@ -443,7 +426,12 @@ export const JsonEditorView = ({
     if (!editor || !mounted) return;
 
     let timeout: number | null = null;
-    const disposable = editor.onDidChangeCursorPosition(() => {
+    const disposable = editor.onDidChangeCursorPosition((e) => {
+      // Skip cursor changes from typing — quickSuggestions handles those.
+      // Only auto-trigger on navigation (click, arrow keys, etc.).
+      // CursorChangeReason: NotSet=0, ContentFlush=1, RecoverFromMarkers=2, Explicit=3, Paste=4, Undo=5, Redo=6
+      if (e.reason !== 3 /* Explicit */) return;
+
       if (timeout) window.clearTimeout(timeout);
       timeout = window.setTimeout(() => {
         try {