fix: move getMonacoEditor to separate file to fix react-refresh lint error

react-refresh/only-export-components disallows mixing component and
non-component exports. Moved the editor ref to monacoEditorRef.ts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/tree-editor/code-mode/CodeModeEditor.tsx

@@ -8,10 +8,7 @@ import { resolutionFlowTheme, THEME_ID } from './resolutionFlowTheme'
 import { createCompletionProvider } from './resolutionFlowCompletions'
 import { CodeModeToolbar } from './CodeModeToolbar'
 import { SyntaxHelpPanel } from './SyntaxHelpPanel'
-
-// Module-level ref so TreeEditorPage can trigger Monaco undo/redo from toolbar buttons
-let _monacoEditor: MonacoEditor.IStandaloneCodeEditor | null = null
-export function getMonacoEditor() { return _monacoEditor }
+import { setMonacoEditor } from './monacoEditorRef'
 
 export function CodeModeEditor() {
   const editorRef = useRef<MonacoEditor.IStandaloneCodeEditor | null>(null)
@@ -58,7 +55,7 @@ export function CodeModeEditor() {
   // Editor mounted
   const handleEditorDidMount: OnMount = useCallback((editor) => {
     editorRef.current = editor
-    _monacoEditor = editor
+    setMonacoEditor(editor)
     editor.focus()
   }, [])
 
@@ -139,7 +136,7 @@ export function CodeModeEditor() {
   // Cleanup on unmount
   useEffect(() => {
     return () => {
-      _monacoEditor = null
+      setMonacoEditor(null)
       if (validationTimeoutRef.current) {
         clearTimeout(validationTimeoutRef.current)
       }

frontend/src/components/tree-editor/code-mode/index.ts

@@ -1,3 +1,4 @@
-export { CodeModeEditor, getMonacoEditor } from './CodeModeEditor'
+export { CodeModeEditor } from './CodeModeEditor'
 export { CodeModeToolbar } from './CodeModeToolbar'
 export { SyntaxHelpPanel } from './SyntaxHelpPanel'
+export { getMonacoEditor } from './monacoEditorRef'

frontend/src/components/tree-editor/code-mode/monacoEditorRef.ts

@@ -0,0 +1,7 @@
+import type { editor as MonacoEditor } from 'monaco-editor'
+
+// Module-level ref so TreeEditorPage can trigger Monaco undo/redo from toolbar buttons
+let _monacoEditor: MonacoEditor.IStandaloneCodeEditor | null = null
+
+export function getMonacoEditor() { return _monacoEditor }
+export function setMonacoEditor(editor: MonacoEditor.IStandaloneCodeEditor | null) { _monacoEditor = editor }