feat(server): scenario mapping (#13404)

fix AI-404

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

* **New Features**
* Introduced scenario-based configuration for copilot, allowing default
model assignments for various AI use cases.
  * Added a new image generation model to the available options.

* **Improvements**
* Refined copilot provider settings by removing deprecated fallback
options and standardizing base URL configuration.
* Enhanced prompt management to support scenario-driven updates and
improved configuration handling.
* Updated admin and settings interfaces to support new scenario
configurations.

* **Bug Fixes**
* Removed deprecated or unused prompts and related references across
platforms for consistency.

* **Other**
* Improved test coverage and updated test assets to reflect prompt and
scenario changes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/admin/src/config.json

@@ -256,6 +256,10 @@
       "type": "Boolean",
       "desc": "Whether to enable the copilot plugin."
     },
+    "scenarios": {
+      "type": "Object",
+      "desc": "The models used in the scene for the copilot, will use this config if enabled."
+    },
     "providers.openai": {
       "type": "Object",
       "desc": "The config for the openai provider.",

packages/frontend/admin/src/modules/settings/config.ts

@@ -142,6 +142,7 @@ export const KNOWN_CONFIG_GROUPS = [
     module: 'copilot',
     fields: [
       'enabled',
+      'scenarios',
       'providers.openai',
       'providers.gemini',
       'providers.perplexity',