fix: detect gh-copilot deprecation and improve GitHub Models 413 errors (#10648)

Address two blocking issues when using GitHub Copilot integrations:

1. ACP mode: detect the gh-copilot CLI deprecation error from stderr
   and surface an actionable message with alternatives instead of
   hanging or showing a cryptic error.

2. GitHub Models (Azure) 413: recognize models.inference.ai.azure.com
   as a known GitHub Models URL, and print a targeted hint explaining
   the hard 8K token limit that makes this endpoint incompatible with
   Hermes' system prompt size.

hermes_cli/models.py

@@ -2525,6 +2525,7 @@ def _is_github_models_base_url(base_url: Optional[str]) -> bool:
     return (
         normalized.startswith(COPILOT_BASE_URL)
         or normalized.startswith("https://models.github.ai/inference")
+        or normalized.startswith("https://models.inference.ai.azure.com")
     )