fix(doctor): skip /models health check for providers that don't support it

Xiaomi MiMo's /v1/models endpoint returns 401 even with a valid API key,
causing hermes doctor to falsely report 'invalid API key'.

Add a `supports_health_check` field to ProviderProfile (default True).
Providers whose /models endpoint doesn't support auth verification can
set it to False. The doctor's dynamic provider discovery now reads this
field instead of hardcoding True.

The xiaomi provider plugin sets supports_health_check=False.

hermes_cli/doctor.py

@@ -287,7 +287,8 @@ def _build_apikey_providers_list() -> list:
                 (_pp.models_url or (_pp.base_url.rstrip("/") + "/models"))
                 if _pp.base_url else None
             )
-            _static.append((_label, _key_vars, _models_url, _base_var, True))
+            _hc = getattr(_pp, "supports_health_check", True)
+            _static.append((_label, _key_vars, _models_url, _base_var, _hc))
     except Exception:
         pass
     return _static