Problem

When running multiple Hermes profiles with separate Telegram bots that share the same Telegram user ID, the session_key collides across bots.

Current behavior:

• Bot A (profile: musk) receives message from user
  → session_key = agent:main:telegram:dm:{user_id}
• Bot B (profile: astock) receives message from same user
  → session_key = agent:main:telegram:dm:{user_id} (collision)

Since build_session_key() in gateway/session.py uses only chat_id for Telegram DMs (no bot identifier), the same Telegram user talking to two different bots on the same Hermes instance produces identical session_keys.

Expected behavior:
Each bot should have isolated session state even when talking to the same user. The session_key should include bot identity so that:

• Bot A → agent:main:telegram:bot:{bot_token_hash}:dm:{user_id}
• Bot B → agent:main:telegram:bot:{bot_token_hash}:dm:{user_id}