AgentRuntime writes scope_id as {user_id}:{agent_id} (73 chars) but:
- DB columns were CHAR(36)/VARCHAR(36), causing Data too long errors
- Memory API queried with agent_id only, returning empty results
- Add _mem_scope() helper to build correct scope_id format
- Update all CRUD queries in agent_memory.py to use _mem_scope()
- Enhance login failure logging in auth.py
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>