Refactor tests for execution plan and add comprehensive storage tests

- Updated `TestModuleSingletons` in `test_execution_plan.py` to reflect new agent templates and playbook names.
- Changed assertions in playbook tests to match updated templates and agents.
- Introduced `test_storage.py` to cover the storage layer, including encryption, BlobStore, and VectorStore functionalities.
- Added tests for S3 interactions, ensuring upload, download, delete, and list operations work as expected.
- Implemented mock tests for Pinecone and Qdrant vector stores to validate upsert, search, and delete operations.

app/agents/__init__.py

@@ -1,5 +1,5 @@
 """Import all agent modules to trigger @registry.register decorators."""
 
-from app.agents import analytics_agent, calendar_agent, email_agent, task_agent
+from app.agents import checkpoint_agent, note_agent, project_agent, task_agent
 
-__all__ = ["analytics_agent", "calendar_agent", "email_agent", "task_agent"]
+__all__ = ["checkpoint_agent", "note_agent", "project_agent", "task_agent"]