chore: remove .notes from repo and add to gitignore

The .notes directory is for local development notes and should not be
committed to the public repo. This removes the accidentally committed
file and prevents future accidental commits.

🐾 Generated with [Letta Code](https://letta.com)

Co-Authored-By: Letta <noreply@letta.com>

.gitignore

@@ -3,6 +3,8 @@
 .letta
 # User-defined skills
 .skills
+# Local notes (not for repo)
+.notes
 
 .idea
 node_modules