feat(server): converge legacy compatibility (#15426)

#### PR Dependency Tree


* **PR #15426** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

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

* **New Features**
* Added workspace BYOK profiles with provider/model catalogs, capability
validation, connection probing, credential rotation, reordering, and
secure local leases.
* Added Copilot route options, selectable targets, managed tiers,
explicit profile/model overrides, and improved streaming with tool
callbacks and abort support.
* Added Copilot availability controls to prevent access when the feature
is disabled.
* **Changes**
* Simplified Copilot configuration and removed legacy provider-specific
settings.
* Removed obsolete model, token-cost, transcript strategy, and provider
metadata fields from public responses.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/copilot/index.ts

@@ -11,6 +11,7 @@ import { StorageModule } from '../../core/storage';
 import { WorkspaceModule } from '../../core/workspaces';
 import { IndexerModule } from '../indexer';
 import { CopilotController } from './controller';
+import { CopilotFeatureGuard, CopilotFeatureService } from './feature';
 import { WorkspaceMcpController } from './mcp/controller';
 import { McpCredentialService } from './mcp/credential';
 import { McpCredentialResolver } from './mcp/resolver';
@@ -34,20 +35,27 @@ const COPILOT_SHARED_IMPORTS = [
 ];
 
 @Module({
-  imports: [...COPILOT_SHARED_IMPORTS],
+  imports: [ServerConfigModule],
+  providers: [CopilotFeatureService, CopilotFeatureGuard],
+  exports: [CopilotFeatureService, CopilotFeatureGuard],
+})
+export class CopilotAvailabilityModule {}
+
+@Module({
+  imports: [...COPILOT_SHARED_IMPORTS, CopilotAvailabilityModule],
   providers: [...COPILOT_KERNEL_PROVIDERS],
-  exports: [...COPILOT_KERNEL_PROVIDERS],
+  exports: [CopilotAvailabilityModule, ...COPILOT_KERNEL_PROVIDERS],
 })
 export class CopilotKernelModule {}
 
 @Module({
-  imports: [PermissionModule],
+  imports: [PermissionModule, CopilotAvailabilityModule],
   providers: [...COPILOT_TRANSCRIPT_REALTIME_PROVIDERS],
 })
 export class CopilotRealtimeModule {}
 
 @Module({
-  imports: [PermissionModule],
+  imports: [PermissionModule, CopilotAvailabilityModule],
   providers: [...COPILOT_CONTEXT_REALTIME_PROVIDERS],
 })
 export class CopilotEmbeddingRealtimeModule {}