chore(server): update config naming (#13419)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Updated scenario names and options for Copilot, including new and
renamed scenarios such as "audio_transcribing,"
"complex_text_generation," "quick_decision_making,"
"quick_text_generation," and "polish_and_summarize."
* Enhanced support for customizing and overriding default model
assignments in Copilot scenarios.

* **Bug Fixes**
* Improved consistency and clarity in scenario configuration and prompt
selection.

* **Documentation**
* Updated descriptions in configuration interfaces to better explain the
ability to use custom models and override defaults.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/admin/src/config.json

@@ -258,7 +258,7 @@
     },
     "scenarios": {
       "type": "Object",
-      "desc": "The models used in the scene for the copilot, will use this config if enabled."
+      "desc": "Use custom models in scenarios and override default settings."
     },
     "providers.openai": {
       "type": "Object",