chore: remove nous-api provider (API key path)

Nous Portal only supports OAuth authentication. Remove the 'nous-api'
provider which allowed direct API key access via NOUS_API_KEY env var.

Removed from:
- hermes_cli/auth.py: PROVIDER_REGISTRY entry + aliases
- hermes_cli/config.py: OPTIONAL_ENV_VARS entry
- hermes_cli/setup.py: setup wizard option + model selection handler
  (reindexed remaining provider choices)
- agent/auxiliary_client.py: docstring references
- tests/test_runtime_provider_resolution.py: nous-api test
- tests/integration/test_web_tools.py: renamed dict key

tests/integration/test_web_tools.py

@@ -579,7 +579,7 @@ class WebToolsTester:
             "results": self.test_results,
             "environment": {
                 "firecrawl_api_key": check_firecrawl_api_key(),
-                "nous_api_key": check_auxiliary_model(),
+                "auxiliary_model": check_auxiliary_model(),
                 "debug_mode": get_debug_session_info()["enabled"]
             }
         }