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/apps/android/App/app/src/main/java/app/affine/pro/Constants.kt

@@ -17,5 +17,4 @@ enum class Prompt(val value: String) {
     MakeItShorter("Make it shorter"),
     ContinueWriting("Continue writing"),
     ChatWithAFFiNEAI("Chat With AFFiNE AI"),
-    SearchWithAFFiNEAI("Search With AFFiNE AI"),
 }