fix: Nous static models use @nous: prefix — v0.50.164 (#885)

fix: Nous static models use @nous: prefix — v0.50.164 (#885)

Follow-up to #854 / PR #870. The previous fix made Nous static IDs
slash-prefixed and added a portal-guard branch to resolve_model_provider().
This tightens the static list to use the explicit @nous: prefix, matching
the format of live-fetched models after ui.js's _fetchLiveModels() portal-
prefix step.

The @provider:model branch in resolve_model_provider() is more explicit and
reliable than the portal-guard fallback. Both static and live-fetched paths
now converge on the same resolver output — and as a side effect, the dedup
check in _fetchLiveModels() now correctly identifies static entries as already
present, eliminating duplicate entries in the dropdown for Nous users.

Verified: all 29 Nous models in the browser dropdown carry @nous: prefix,
routing confirmed correct via resolve_model_provider() for all 4 static IDs,
1941 tests passing.

Closes #854.

api/config.py

@@ -613,10 +613,10 @@ _PROVIDER_MODELS = {
         {"id": "deepseek-reasoner", "label": "DeepSeek Reasoner"},
     ],
     "nous": [
-        {"id": "anthropic/claude-opus-4.6",     "label": "Claude Opus 4.6 (via Nous)"},
-        {"id": "anthropic/claude-sonnet-4.6",   "label": "Claude Sonnet 4.6 (via Nous)"},
-        {"id": "openai/gpt-5.4-mini",           "label": "GPT-5.4 Mini (via Nous)"},
-        {"id": "google/gemini-3.1-pro-preview", "label": "Gemini 3.1 Pro Preview (via Nous)"},
+        {"id": "@nous:anthropic/claude-opus-4.6",     "label": "Claude Opus 4.6 (via Nous)"},
+        {"id": "@nous:anthropic/claude-sonnet-4.6",   "label": "Claude Sonnet 4.6 (via Nous)"},
+        {"id": "@nous:openai/gpt-5.4-mini",           "label": "GPT-5.4 Mini (via Nous)"},
+        {"id": "@nous:google/gemini-3.1-pro-preview", "label": "Gemini 3.1 Pro Preview (via Nous)"},
     ],
     "zai": [
         {"id": "glm-5.1", "label": "GLM-5.1"},