feat(core): add ai playground feature flag and remove model switch feature flag (#12934)

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

## Summary by CodeRabbit

* **New Features**
* Added support for the "AI Playground" experimental feature, including
new settings and localization entries.

* **Refactor**
* Renamed configuration and service references from "Model Switch" to
"Playground" across the AI chat and playground interfaces.
* Updated feature flag from "enable_ai_model_switch" to
"enable_ai_playground" for consistency.

* **Bug Fixes**
* The "Model" submenu in AI chat preferences is now always visible,
simplifying menu options.

* **Chores**
  * Removed outdated Claude model options from the chat prompt.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/modules/ai-button/index.ts

@@ -7,8 +7,8 @@ import { FeatureFlagService } from '../feature-flag';
 import { GlobalStateService } from '../storage';
 import { AIButtonProvider } from './provider/ai-button';
 import { AIButtonService } from './services/ai-button';
-import { AIModelSwitchService } from './services/model-switch';
 import { AINetworkSearchService } from './services/network-search';
+import { AIPlaygroundService } from './services/playground';
 import { AIReasoningService } from './services/reasoning';
 
 export const configureAIButtonModule = (framework: Framework) => {
@@ -28,6 +28,6 @@ export function configureAIReasoningModule(framework: Framework) {
   framework.service(AIReasoningService, [GlobalStateService]);
 }
 
-export function configureAIModelSwitchModule(framework: Framework) {
-  framework.service(AIModelSwitchService, [FeatureFlagService]);
+export function configureAIPlaygroundModule(framework: Framework) {
+  framework.service(AIPlaygroundService, [FeatureFlagService]);
 }

packages/frontend/core/src/modules/ai-button/services/playground.ts

@@ -6,7 +6,7 @@ import { Service } from '@toeverything/infra';
 
 import type { FeatureFlagService } from '../../feature-flag';
 
-export class AIModelSwitchService extends Service {
+export class AIPlaygroundService extends Service {
   constructor(private readonly featureFlagService: FeatureFlagService) {
     super();
 
@@ -22,5 +22,5 @@ export class AIModelSwitchService extends Service {
   visible: Signal<boolean | undefined>;
 
   private readonly _visible$ =
-    this.featureFlagService.flags.enable_ai_model_switch.$;
+    this.featureFlagService.flags.enable_ai_playground.$;
 }

packages/frontend/core/src/modules/feature-flag/constant.ts

@@ -26,7 +26,7 @@ export const AFFINE_FLAGS = {
     configurable: false,
     defaultState: true,
   },
-  enable_ai_model_switch: {
+  enable_ai_playground: {
     category: 'affine',
     displayName:
       'com.affine.settings.workspace.experimental-features.enable-ai-model-switch.name',

packages/frontend/core/src/modules/index.ts

@@ -3,8 +3,8 @@ import { type Framework } from '@toeverything/infra';
 
 import {
   configureAIButtonModule,
-  configureAIModelSwitchModule,
   configureAINetworkSearchModule,
+  configureAIPlaygroundModule,
   configureAIReasoningModule,
 } from './ai-button';
 import { configureAppSidebarModule } from './app-sidebar';
@@ -107,7 +107,7 @@ export function configureCommonModules(framework: Framework) {
   configureCommonGlobalStorageImpls(framework);
   configureAINetworkSearchModule(framework);
   configureAIReasoningModule(framework);
-  configureAIModelSwitchModule(framework);
+  configureAIPlaygroundModule(framework);
   configureAIButtonModule(framework);
   configureTemplateDocModule(framework);
   configureBlobManagementModule(framework);