feat: add notes preview helper with tests

Made-with: Cursor

backend/utils/notes-preview.js

@@ -0,0 +1,26 @@
+function computeNotesPreview(notes) {
+  if (!notes || notes.trim() === '') {
+    return { has_notes: false, notes_preview: null };
+  }
+
+  const firstParagraph = notes.split(/\n\n/)[0];
+
+  const stripped = firstParagraph
+    .replace(/^#{1,6}\s+/gm, '')       // headers
+    .replace(/\*\*(.+?)\*\*/g, '$1')   // bold
+    .replace(/\*(.+?)\*/g, '$1')       // italic with *
+    .replace(/_(.+?)_/g, '$1')         // italic with _
+    .replace(/\[([^\]]+)\]\([^)]+\)/g, '$1') // links
+    .replace(/^[-*+]\s+/gm, '')        // list markers
+    .replace(/\n/g, ' ')               // collapse remaining newlines
+    .replace(/\s+/g, ' ')              // collapse whitespace
+    .trim();
+
+  const truncated = stripped.length > 150
+    ? stripped.slice(0, 150) + '...'
+    : stripped;
+
+  return { has_notes: true, notes_preview: truncated };
+}
+
+module.exports = { computeNotesPreview };