fix(gateway): thread-safe SessionStore — protect _entries with threading.Lock

[teknium1]

Summary

Salvage of PR #3012 by @Kewe63. Removed unrelated changes (delivery.py case-sensitivity fix, hermes_state.py schema tracking) and stripped the UTC timezone switch to keep the change focused on threading.

Problem

SessionStore._entries was read and mutated without synchronisation, causing race conditions when multiple platforms (Telegram + Discord) received messages concurrently on the same gateway process. Two threads could simultaneously pass the session_key in self._entries check and create duplicate sessions for the same user, splitting conversation history.

Fix

• Added threading.Lock() to protect all _entries / _loaded mutations
• Split _ensure_loaded() into public wrapper + internal _ensure_loaded_locked()
• SQLite I/O performed outside the lock to avoid blocking during slow disk ops
• _save() stays inside the lock since it reads _entries for serialization

Test results

All 1429 gateway tests pass. Live PTY-tested with full CLI session — session created, multi-turn conversation, clean exit, DB records verified (started_at, ended_at, end_reason, messages all correct).

[github-actions]

⚠️ Supply Chain Risk Detected

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⚠️ WARNING: Install hook files modified

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Files:

hermes_cli/setup.py

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