fix(nous): surface Portal-flagged free models in picker even when curated list is stale (#24082)

Free-tier users were seeing 'No free models currently available.' in the
`hermes model` and post-login pickers even though qwen/qwen3.6-plus is
free on the Portal right now. Three independent breakages compounded:

1. The docs-hosted catalog manifest at website/static/api/model-catalog.json
   was not regenerated when _PROVIDER_MODELS['nous'] was updated, so users
   fetching the manifest got a list that didn't include qwen/qwen3.6-plus.
2. _resolve_nous_pricing_credentials() returned ('', '') on any auth blip,
   collapsing get_pricing_for_provider('nous') to {} and making every
   curated model fall through the free-tier filter as 'paid'.
3. Even with healthy pricing, the picker only ever showed models from the
   in-repo curated list intersected with live pricing — a Portal-flagged
   free model not yet in the curated list could never appear.

Changes:
- hermes_cli/models.py: new union_with_portal_free_recommendations() that
  augments the curated list with Portal freeRecommendedModels entries
  (with synthetic free pricing so partition keeps them). The Portal's
  /api/nous/recommended-models endpoint is now the source of truth for
  free-tier surfacing — old Hermes builds will see new free models
  without a CLI release.
- hermes_cli/models.py: _resolve_nous_pricing_credentials() falls back to
  the public inference base URL when runtime cred resolution fails.
  The /v1/models endpoint exposes pricing without auth, so silently
  returning {} just because a refresh token expired was wrong.
- hermes_cli/auth.py + hermes_cli/main.py: both free-tier picker call
  sites call union_with_portal_free_recommendations() before partition.
- tests/hermes_cli/test_models.py: 7 tests covering union behaviour
  (prepend, dedup, end-to-end with stale pricing, empty/missing/error
  payloads, invalid entries).
- tests/hermes_cli/test_model_catalog.py: drift guard
  TestManifestMatchesInRepoLists fails CI when _PROVIDER_MODELS['nous']
  or OPENROUTER_MODELS is edited without re-running
  scripts/build_model_catalog.py. Verified empirically that removing a
  manifest entry triggers an assertion with an actionable error message.

Validation:
- 133/133 targeted tests pass (test_models, test_model_catalog,
  test_auth_nous_provider).
- Live E2E against the real Portal:
  - Stale curated list ['claude-opus','claude-sonnet','gpt-5.4'] (no
    qwen) → after union: ['qwen/qwen3.6-plus', ...] →
    partition(free_tier=True): selectable=['qwen/qwen3.6-plus'].
  - Simulated expired refresh token → anon fetch returns 403 pricing
    entries including qwen/qwen3.6-plus -> {prompt:0, completion:0}.
- ruff: clean.

hermes_cli/auth.py

@@ -5251,6 +5251,7 @@ def _login_nous(args, pconfig: ProviderConfig) -> None:
             from hermes_cli.models import (
                 get_curated_nous_model_ids, get_pricing_for_provider,
                 check_nous_free_tier, partition_nous_models_by_tier,
+                union_with_portal_free_recommendations,
             )
             model_ids = get_curated_nous_model_ids()
 
@@ -5260,6 +5261,15 @@ def _login_nous(args, pconfig: ProviderConfig) -> None:
                 pricing = get_pricing_for_provider("nous")
                 free_tier = check_nous_free_tier()
                 if free_tier:
+                    # The Portal's freeRecommendedModels endpoint is the
+                    # source of truth for what's free *right now*. Augment
+                    # the curated list with anything new the Portal flags
+                    # as free so users on older Hermes builds still see
+                    # newly-launched free models without a CLI release.
+                    _portal_for_recs = auth_state.get("portal_base_url", "")
+                    model_ids, pricing = union_with_portal_free_recommendations(
+                        model_ids, pricing, _portal_for_recs,
+                    )
                     model_ids, unavailable_models = partition_nous_models_by_tier(
                         model_ids, pricing, free_tier=True,
                     )