feat(server): realtime handle & migration (#15487)

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

* **New Features**
  * Retry failed Copilot transcription tasks in real time.
  * Retried tasks resume processing and report updated status.
* Managed Copilot provider models can be omitted to use provider
defaults.

* **Bug Fixes**
* Improved handling of incomplete BYOK profiles, including safe
replacement of legacy records.
  * Duplicate profile creation now returns a clear validation error.
* Improved transcript processing reliability by preventing duplicate or
stale dispatches.

* **Migration**
* Consolidated legacy managed-provider settings while preserving
existing profiles and defaults.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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

@@ -3,6 +3,7 @@ import { Cron, CronExpression } from '@nestjs/schedule';
 
 import { JobQueue, OneDay, OnJob } from '../../base';
 import { Models } from '../../models';
+import { CopilotTranscriptionRetryService } from './transcript/retry';
 
 const BACKGROUND_COPILOT_JOB_PRIORITY = 100;
 
@@ -19,9 +20,15 @@ export class CopilotCronJobs {
 
   constructor(
     private readonly models: Models,
-    private readonly jobs: JobQueue
+    private readonly jobs: JobQueue,
+    private readonly transcriptRetry: CopilotTranscriptionRetryService
   ) {}
 
+  @Cron(CronExpression.EVERY_MINUTE)
+  async reconcileTranscriptDispatches() {
+    await this.transcriptRetry.reconcileDispatches();
+  }
+
   @Cron(CronExpression.EVERY_DAY_AT_MIDNIGHT)
   async dailyCleanupJob() {
     await this.jobs.add(