Add error marker when invalid main function (#9489)

## Before

![image](https://github.com/user-attachments/assets/f6af6721-0896-48b5-8556-9d2a9c19de06)

## After

![image](https://github.com/user-attachments/assets/c59407c8-8244-4906-9d05-713909a19c33)

packages/twenty-ui/src/input/code-editor/components/CodeEditor.tsx

@@ -1,11 +1,14 @@
 import { useTheme, css } from '@emotion/react';
-import Editor, { EditorProps } from '@monaco-editor/react';
+import Editor, { EditorProps, Monaco } from '@monaco-editor/react';
 import { codeEditorTheme } from '@ui/input';
 import { isDefined } from '@ui/utilities';
 import styled from '@emotion/styled';
+import { useState } from 'react';
+import { editor } from 'monaco-editor';
 
 type CodeEditorProps = Omit<EditorProps, 'onChange'> & {
   onChange?: (value: string) => void;
+  setMarkers?: (value: string) => editor.IMarkerData[];
   withHeader?: boolean;
 };
 
@@ -35,12 +38,31 @@ export const CodeEditor = ({
   language,
   onMount,
   onChange,
+  setMarkers,
   onValidate,
   height = 450,
   withHeader = false,
   options,
 }: CodeEditorProps) => {
   const theme = useTheme();
+  const [monaco, setMonaco] = useState<Monaco | undefined>(undefined);
+  const [editor, setEditor] = useState<
+    editor.IStandaloneCodeEditor | undefined
+  >(undefined);
+
+  const setModelMarkers = (
+    editor: editor.IStandaloneCodeEditor | undefined,
+    monaco: Monaco | undefined,
+  ) => {
+    const model = editor?.getModel();
+    if (!isDefined(model)) {
+      return;
+    }
+    const customMarkers = setMarkers?.(model.getValue());
+    if (isDefined(customMarkers)) {
+      monaco?.editor.setModelMarkers(model, 'customMarker', customMarkers);
+    }
+  };
 
   return (
     <StyledEditor
@@ -49,17 +71,22 @@ export const CodeEditor = ({
       value={value}
       language={language}
       onMount={(editor, monaco) => {
+        setMonaco(monaco);
+        setEditor(editor);
         monaco.editor.defineTheme('codeEditorTheme', codeEditorTheme(theme));
         monaco.editor.setTheme('codeEditorTheme');
-
         onMount?.(editor, monaco);
+        setModelMarkers(editor, monaco);
       }}
       onChange={(value) => {
         if (isDefined(value)) {
           onChange?.(value);
+          setModelMarkers(editor, monaco);
         }
       }}
-      onValidate={onValidate}
+      onValidate={(markers) => {
+        onValidate?.(markers);
+      }}
       options={{
         overviewRulerLanes: 0,
         scrollbar: {