test(cli): cover minimax-oauth resolution, refresh, menu wiring

Add and extend tests for the minimax-oauth provider across three test
modules.

New file: tests/test_minimax_oauth.py (15 tests)
  - test_pkce_pair_produces_valid_s256: verifies PKCE verifier/challenge
    pair produces a valid S256 hash and correct lengths
  - test_request_user_code_happy_path: mocks httpx, verifies correct
    POST parameters and response parsing
  - test_request_user_code_state_mismatch_raises: verifies CSRF guard
  - test_request_user_code_non_200_raises: verifies HTTP error handling
  - test_poll_token_pending_then_success: verifies polling loop retries
    on 'pending' and returns on 'success'
  - test_poll_token_error_raises: verifies 'error' status raises AuthError
  - test_poll_token_timeout_raises: verifies deadline expiry raises
  - test_refresh_skip_when_not_expired: verifies no HTTP call when token
    is fresh
  - test_refresh_updates_access_token: verifies new access/refresh tokens
    stored on successful refresh
  - test_refresh_reuse_triggers_relogin_required: verifies
    relogin_required=True on invalid_grant/refresh_token_reused
  - test_resolve_credentials_requires_login: verifies AuthError when no
    stored state
  - test_provider_registry_contains_minimax_oauth: PROVIDER_REGISTRY key
  - test_minimax_oauth_alias_resolves: portal/global/underscore aliases
  - test_get_minimax_oauth_auth_status_not_logged_in
  - test_get_minimax_oauth_auth_status_logged_in

Extended: tests/hermes_cli/test_runtime_provider_resolution.py
  - test_minimax_oauth_runtime_returns_anthropic_messages_mode
  - test_minimax_oauth_runtime_uses_inference_base_url

Extended: tests/hermes_cli/test_api_key_providers.py
  - TestMinimaxOAuthProvider class (8 tests) covering registry keys,
    auth_type, endpoints, client_id, aliases, CANONICAL_PROVIDERS
    listing, _PROVIDER_MODELS entries, and aux model

tests/hermes_cli/test_api_key_providers.py

@@ -1033,3 +1033,63 @@ class TestHuggingFaceModels:
         from hermes_cli.models import _PROVIDER_LABELS
         assert "huggingface" in _PROVIDER_LABELS
         assert _PROVIDER_LABELS["huggingface"] == "Hugging Face"
+
+
+# =============================================================================
+# MiniMax OAuth provider tests (added by feat/minimax-oauth-provider)
+# =============================================================================
+
+class TestMinimaxOAuthProvider:
+    """Tests for the minimax-oauth OAuth provider."""
+
+    def test_minimax_oauth_in_provider_registry(self):
+        assert "minimax-oauth" in PROVIDER_REGISTRY
+        pconfig = PROVIDER_REGISTRY["minimax-oauth"]
+        assert pconfig.auth_type == "oauth_minimax"
+        assert pconfig.id == "minimax-oauth"
+
+    def test_minimax_oauth_has_correct_endpoints(self):
+        from hermes_cli.auth import (
+            MINIMAX_OAUTH_GLOBAL_BASE,
+            MINIMAX_OAUTH_GLOBAL_INFERENCE,
+            MINIMAX_OAUTH_CN_BASE,
+            MINIMAX_OAUTH_CN_INFERENCE,
+        )
+        pconfig = PROVIDER_REGISTRY["minimax-oauth"]
+        assert pconfig.portal_base_url == MINIMAX_OAUTH_GLOBAL_BASE
+        assert pconfig.inference_base_url == MINIMAX_OAUTH_GLOBAL_INFERENCE
+        assert pconfig.extra["cn_portal_base_url"] == MINIMAX_OAUTH_CN_BASE
+        assert pconfig.extra["cn_inference_base_url"] == MINIMAX_OAUTH_CN_INFERENCE
+
+    def test_minimax_oauth_alias_resolves_portal(self):
+        result = resolve_provider("minimax-portal")
+        assert result == "minimax-oauth"
+
+    def test_minimax_oauth_alias_resolves_global(self):
+        result = resolve_provider("minimax-global")
+        assert result == "minimax-oauth"
+
+    def test_minimax_oauth_alias_resolves_underscore(self):
+        result = resolve_provider("minimax_oauth")
+        assert result == "minimax-oauth"
+
+    def test_minimax_oauth_listed_in_canonical_providers(self):
+        from hermes_cli.models import CANONICAL_PROVIDERS
+        slugs = [p.slug for p in CANONICAL_PROVIDERS]
+        assert "minimax-oauth" in slugs
+
+    def test_minimax_oauth_models_alias_in_models_py(self):
+        from hermes_cli.models import _PROVIDER_ALIASES
+        assert _PROVIDER_ALIASES.get("minimax-portal") == "minimax-oauth"
+        assert _PROVIDER_ALIASES.get("minimax-global") == "minimax-oauth"
+        assert _PROVIDER_ALIASES.get("minimax_oauth") == "minimax-oauth"
+
+    def test_minimax_oauth_has_models(self):
+        from hermes_cli.models import _PROVIDER_MODELS
+        models = _PROVIDER_MODELS.get("minimax-oauth", [])
+        assert len(models) >= 1
+
+    def test_minimax_oauth_aux_model_registered(self):
+        from agent.auxiliary_client import _API_KEY_PROVIDER_AUX_MODELS
+        assert "minimax-oauth" in _API_KEY_PROVIDER_AUX_MODELS
+        assert _API_KEY_PROVIDER_AUX_MODELS["minimax-oauth"]  # non-empty