Hermes sessions have no model picker in the chat composer

[turingcat]

Summary

Hermes sessions do not expose a model picker in the chat composer. This affects both the built-in Hermes agent and custom Hermes profiles launched with their own HERMES_HOME.

Hermes keeps the active model in model.default inside the profile's config.yaml, but its ACP adapter currently does not advertise a model configOption. Codeg only renders agent-advertised configuration options in the composer, so Hermes users must leave the conversation and edit agent settings to change models.

Steps to reproduce

1. Configure the built-in Hermes agent, or register a custom agent whose command is hermes / hermes-agent and whose environment points HERMES_HOME at a profile.
2. Configure a provider and model for that profile.
3. Start a Hermes conversation.
4. Open the composer selectors.

Actual behavior

No model selector is shown, even though the profile has a current model and its provider may expose a model catalogue.

Expected behavior

• Show the current Hermes model in the chat composer.
• List models from the configured provider when its API supports discovery.
• Support custom Hermes profiles without reading or writing the default profile by mistake.
• Persist a selection to that profile's config.yaml.
• Reconnect the session after the current turn finishes, because Hermes reads its config at process startup.
• Mark other running sessions for the same profile as stale so they do not silently remain on the old model.
• Do not add a duplicate picker if a future Hermes ACP adapter advertises its own model option.

Environment

• Codeg 0.30.10
• macOS arm64

I have a tested implementation ready and will open a linked PR.