feat: unify model selection and complete favorite settings

apps/admin_console/services/model_settings_service.py

@@ -80,11 +80,9 @@ def get_model_settings() -> dict:
         "tool_fallback_no_progress_attempts": settings.ARTEMIS_TOOL_FALLBACK_MAX_NO_PROGRESS_ATTEMPTS,
         "reasoning_effort": settings.OPENAI_REASONING_EFFORT,
         "model_presets": [
+            "gpt-6-luna",
             "gpt-6.1-sol",
             "gpt-6-astra",
-            "gpt-5.6-luna",
-            "gpt-6-luna",
-            "mimo-v2.6-flash",
             "mimo-v2.6-pro",
         ],
         "env_path": str(get_env_file()),