fix(config): accept 'model' key as alias for 'default' in model config (#3603)

Users intuitively write model: { model: my-model } instead of
model: { default: my-model } and it silently falls back to the
hardcoded default. Now both spellings work across all three config
consumers: runtime_provider, CLI, and gateway.

Co-authored-by: ygd58 <ygd58@users.noreply.github.com>

hermes_cli/runtime_provider.py

@@ -63,6 +63,9 @@ def _get_model_config() -> Dict[str, Any]:
     model_cfg = config.get("model")
     if isinstance(model_cfg, dict):
         cfg = dict(model_cfg)
+        # Accept "model" as alias for "default" (users intuitively write model.model)
+        if not cfg.get("default") and cfg.get("model"):
+            cfg["default"] = cfg["model"]
         default = (cfg.get("default") or "").strip()
         base_url = (cfg.get("base_url") or "").strip()
         is_local = "localhost" in base_url or "127.0.0.1" in base_url