fix AI-404
<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## 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 -->
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