fix: silent no-model default is GLM-5.2, never the Anthropic flagship (#64635)

When a user starts a chat without ever selecting a model (GUI Chat App
onboarding, provider-set-but-model-missing config, empty model.default),
every silent fallback path resolved to the first curated catalog entry —
anthropic/claude-fable-5, the priciest flagship. Users were silently
billed for the most expensive model without opting in.

- hermes_cli/models.py: add PREFERRED_SILENT_DEFAULT_MODEL (z-ai/glm-5.2)
  + pick_silent_default_model() helper; point the nous silent-default
  override at it and add an openrouter override (previously resolved to
  "" and let downstream paths land on the flagship).
- hermes_cli/web_server.py: /api/model/recommended-default (the endpoint
  the Desktop onboarding confirm card reads) now picks GLM-5.2 when the
  provider's list carries it instead of blindly taking entry [0].
- tui_gateway/server.py: _resolve_model()'s last-resort literal was
  anthropic/claude-sonnet-4; now PREFERRED_SILENT_DEFAULT_MODEL.
- tests: update empty-model fallback tests for the new contract.

hermes_cli/web_server.py

@@ -5576,6 +5576,7 @@ def get_recommended_default_model(provider: str = ""):
                 get_pricing_for_provider,
                 check_nous_free_tier,
                 partition_nous_models_by_tier,
+                pick_silent_default_model,
                 union_with_portal_free_recommendations,
                 union_with_portal_paid_recommendations,
             )
@@ -5604,21 +5605,25 @@ def get_recommended_default_model(provider: str = ""):
                     model_ids, pricing, portal_url
                 )
 
-            model = model_ids[0] if model_ids else ""
+            model = pick_silent_default_model(model_ids)
             return {"provider": "nous", "model": model, "free_tier": bool(free_tier)}
         except Exception:
             _log.exception("GET /api/model/recommended-default (nous) failed")
             return {"provider": "nous", "model": "", "free_tier": None}
 
-    # Non-Nous: first curated model for the provider, matching prior behaviour.
+    # Non-Nous: preferred silent default when the provider's curated list
+    # carries it, else the first curated model. Aggregator lists lead with the
+    # priciest Anthropic flagship (claude-fable-5), which must never be the
+    # model a user lands on without explicitly picking it.
     try:
         from hermes_cli.inventory import build_models_payload, load_picker_context
+        from hermes_cli.models import pick_silent_default_model
 
         payload = build_models_payload(load_picker_context())
         for row in payload.get("providers", []):
             if str(row.get("slug", "")).lower() == slug:
-                models = row.get("models") or []
-                return {"provider": slug, "model": models[0] if models else "", "free_tier": None}
+                models = [str(m) for m in (row.get("models") or [])]
+                return {"provider": slug, "model": pick_silent_default_model(models), "free_tier": None}
         return {"provider": slug, "model": "", "free_tier": None}
     except Exception:
         _log.exception("GET /api/model/recommended-default failed")