Incorrect use of threading. Lock in Async Methods (MemoryStorage, TranscriptMemoryStore)

[cleemullins]

Use of threading. Lock in Async Methods (MemoryStorage, TranscriptMemoryStore)

Files: memory_storage.py, transcript_memory_store.py

Pattern: performing trivial dict/list operations inside with self._lock: in async def. Currently safe because no awaits inside critical sections. However:

• If future changes add awaits inside the with blocks, deadlocks/blocking risk arises (like Cosmos issue).
• In an asyncio-only deployment (single thread), threading.Lock is unnecessary; an asyncio.Lock would be more semantically correct.
• In free-threaded Python (3.13t/3.14t) scenarios, using a standard Lock may still be fine, but code clarity improves with explicit async primitives.
• Recommendation: Migrate to asyncio.Lock unless true multi-thread writers are expected. Document invariants.