feat(models): remote model catalog manifest for OpenRouter + Nous Portal (#16033)

OpenRouter and Nous Portal curated picker lists now resolve via a JSON
manifest served by the docs site, falling back to the in-repo snapshot
when unreachable. Lets us update model lists without shipping a release.

Live URL: https://hermes-agent.nousresearch.com/docs/api/model-catalog.json
(source at website/static/api/model-catalog.json; auto-deploys via the
existing deploy-site.yml GitHub Pages pipeline on every merge to main).

Schema (v1) carries id + optional description + free-form metadata at
manifest, provider, and model levels. Pricing and context length stay
live-fetched via existing machinery (/v1/models endpoints, models.dev).

Config (new model_catalog section, default enabled):
  model_catalog.url       master manifest URL
  model_catalog.ttl_hours disk cache TTL (default 24h)
  model_catalog.providers.<name>.url   optional per-provider override

Fetch pipeline: in-process cache -> disk cache (fresh < TTL) -> HTTP
fetch -> disk-cache-on-failure fallback -> in-repo snapshot as last
resort. Never raises to callers; at worst returns the bundled list.

Changes:
- website/static/api/model-catalog.json    initial manifest (35 OR + 31 Nous)
- scripts/build_model_catalog.py           regenerator from in-repo lists
- hermes_cli/model_catalog.py              fetch + validate + cache module
- hermes_cli/models.py                     fetch_openrouter_models() +
                                           new get_curated_nous_model_ids()
- hermes_cli/main.py, hermes_cli/auth.py   Nous flows use the helper
- hermes_cli/config.py                     model_catalog defaults
- website/docs/reference/model-catalog.md  + sidebars.ts
- tests/hermes_cli/test_model_catalog.py   21 tests (validation, fetch
                                           success/failure, accessors,
                                           disabled, overrides, integration)

hermes_cli/auth.py

@@ -4244,10 +4244,10 @@ def _login_nous(args, pconfig: ProviderConfig) -> None:
                 )
 
             from hermes_cli.models import (
-                _PROVIDER_MODELS, get_pricing_for_provider,
+                get_curated_nous_model_ids, get_pricing_for_provider,
                 check_nous_free_tier, partition_nous_models_by_tier,
             )
-            model_ids = _PROVIDER_MODELS.get("nous", [])
+            model_ids = get_curated_nous_model_ids()
 
             print()
             unavailable_models: list = []