Hermes Beta v0.1.13-beta.1

Beta pre-release.

Fix: changing the model inside a chat now surfaces the result. The app sends the /model … --session slash; previously the outcome was discarded, so a failed switch looked like nothing happened. It now shows the gateway's message — success, or the actual error ('Could not resolve credentials for …', 'slash worker closed pipe'). The underlying switch failures are a gateway-side bug (the slash worker runs against the wrong profile, Hermes #18594) that needs a Hermes update.