feat: Add notes search endpoint for enhanced global search

- Add searchNotes service function with company/project info
- Add /notes/search endpoint for searching notes content
- Returns matching notes with linked company/project names

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/routes/note.routes.js

@@ -18,6 +18,9 @@ router.use(authenticate);
 // Get all notes (admin only - returns all notes system-wide)
 router.get('/', requireAdmin, noteController.getAllNotes);
 
+// Search notes with company/project info (must be before /:noteId to avoid route conflict)
+router.get('/search', noteController.searchNotes);
+
 // Get my reminders (must be before /:noteId to avoid route conflict)
 router.get('/my-reminders', noteController.getMyReminders);