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

agent/auxiliary_client.py

@@ -547,7 +547,7 @@ def resolve_provider_client(
     Args:
         provider: Provider identifier.  One of:
             "openrouter", "nous", "openai-codex" (or "codex"),
-            "zai", "kimi-coding", "minimax", "minimax-cn", "nous-api",
+            "zai", "kimi-coding", "minimax", "minimax-cn",
             "custom" (OPENAI_BASE_URL + OPENAI_API_KEY),
             "auto" (full auto-detection chain).
         model: Model slug override.  If None, uses the provider's default
@@ -674,7 +674,7 @@ def resolve_provider_client(
             return resolve_provider_client("nous", model, async_mode)
         if provider == "openai-codex":
             return resolve_provider_client("openai-codex", model, async_mode)
-        # nous-api is api_key type so it's handled above
+        # Other OAuth providers not directly supported
         logger.warning("resolve_provider_client: OAuth provider %s not "
                        "directly supported, try 'auto'", provider)
         return None, None