feat(gateway): add model and provider info to /status command

[KickUasS]

Enhance the /status command to display current model and provider information.

Changes made:

• Read model/provider from config.yaml as baseline
• Check _session_model_overrides for active session-level overrides
• Display model name with (session override) indicator when applicable
• Show provider label for better readability

This makes it easy to verify which model is being used by the gateway.

[alt-glitch]

Likely duplicate of #11079 — same feature (add model/provider info to /status), same file changed (gateway/run.py).

[teknium1]

Thanks for addressing gateway model visibility. The broader model/provider status feature was already salvaged into main in ead38107a2f2b6d6a71e92e978fe98a684bd3be8, but the session-override edge case remains worth preserving.

Problems

• This patch targets gateway/run.py, but /status now lives in gateway/slash_commands.py:493 after 619bd782738adfa87544d0fda7a1114defe86e4c; it needs a targeted port.
• The current gap is specifically post-/model: the handler stores an override at gateway/slash_commands.py:1868-1883 and evicts the cache at :1891, while /status falls back through SessionDB/config at :582-610. hermes_state.py:2363-2375 persists only the model column, so provider can be stale after a cross-provider session switch.
• tests/gateway/test_status_command.py:180-276 has model/provider coverage but no immediate /model → /status regression case.

Suggested changes

• Port override-aware resolution into GatewaySlashCommandsMixin._handle_status_command, preserving the localized status output at gateway/slash_commands.py:605-610.
• Cover an evicted-cache, cross-provider session switch; include the persisted SessionEntry.model_override path.

Automated hermes-sweeper review.