feat(server): realtime notification & task status (#14934)

#### PR Dependency Tree


* **PR #14934** 👈

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**
* Full realtime platform added: live notifications, comments, embedding
progress, and transcription task updates via realtime subscriptions.

* **Chores**
* Frontend switched from polling/GraphQL queries to realtime channels;
legacy query fields marked deprecated and client libs updated to use
realtime APIs.

[![Review Change
Stack](https://storage.googleapis.com/coderabbit_public_assets/review-stack-in-coderabbit-ui.svg)](https://app.coderabbit.ai/change-stack/toeverything/AFFiNE/pull/14934)
<!-- end of auto-generated comment: release notes by coderabbit.ai -->


#### PR Dependency Tree


* **PR #14934** 👈
  * **PR #14936**

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

packages/backend/server/src/plugins/copilot/transcript/service.ts

@@ -9,6 +9,7 @@ import {
   OnJob,
   sniffMime,
 } from '../../../base';
+import type { RealtimePublisher } from '../../../core/realtime';
 import { Models } from '../../../models';
 import { CopilotAccessPolicy } from '../access';
 import { PromptService } from '../prompt';
@@ -32,6 +33,10 @@ const TRANSCRIPT_ACTION_ID = 'transcript.audio.gemini';
 const TRANSCRIPT_ACTION_VERSION = 'v1';
 const TRANSCRIPT_STRATEGY = 'gemini';
 
+export function transcriptTaskRoom(workspaceId: string, taskId: string) {
+  return `copilot:transcript:${workspaceId}:${taskId}`;
+}
+
 export type TranscriptionJob = {
   id: string;
   status: AiJobStatus;
@@ -62,7 +67,8 @@ export class CopilotTranscriptionService {
     private readonly tasks: TaskPolicy,
     private readonly prompts: PromptService,
     private readonly actionBridge: ActionRuntimeBridge,
-    @Optional() private readonly access?: CopilotAccessPolicy
+    @Optional() private readonly access?: CopilotAccessPolicy,
+    @Optional() private readonly realtime?: RealtimePublisher
   ) {}
 
   private parseTaskPayload(payload: unknown): TranscriptionPayloadV2 {
@@ -252,6 +258,7 @@ export class CopilotTranscriptionService {
       modelId: model,
     });
     await this.models.copilotTranscriptTask.markRunning(task.id);
+    this.publishTaskChanged(workspaceId, task.id, AiJobStatus.running);
 
     return { id: task.id, status: AiJobStatus.running, infos };
   }
@@ -294,6 +301,7 @@ export class CopilotTranscriptionService {
       retryOf: task.actionRunId ?? undefined,
     });
     await this.models.copilotTranscriptTask.markRunning(taskId);
+    this.publishTaskChanged(workspaceId, taskId, AiJobStatus.running);
     return {
       id: taskId,
       status: AiJobStatus.running,
@@ -389,6 +397,11 @@ export class CopilotTranscriptionService {
         },
         onRunCreated: async ({ runId }) => {
           await this.models.copilotTranscriptTask.markRunning(taskId, runId);
+          this.publishTaskChanged(
+            task.workspaceId,
+            taskId,
+            AiJobStatus.running
+          );
         },
         prepareStructuredRoutes: {
           stepId: 'transcribe',
@@ -425,6 +438,7 @@ export class CopilotTranscriptionService {
         protectedResult: parsedResult,
         errorCode: null,
       });
+      this.publishTaskChanged(task.workspaceId, taskId, AiJobStatus.finished);
     } catch (error) {
       await this.models.copilotTranscriptTask.complete(taskId, {
         status: 'failed',
@@ -434,7 +448,27 @@ export class CopilotTranscriptionService {
         errorCode:
           error instanceof Error ? error.message : 'transcript_task_failed',
       });
+      this.publishTaskChanged(
+        task.workspaceId,
+        taskId,
+        AiJobStatus.failed,
+        error instanceof Error ? error.message : 'transcript_task_failed'
+      );
       throw error;
     }
   }
+
+  private publishTaskChanged(
+    workspaceId: string,
+    taskId: string,
+    status: AiJobStatus,
+    error?: string
+  ) {
+    this.realtime?.publish(
+      'copilot.transcript.task.changed',
+      { workspaceId, taskId },
+      { taskId, status, error },
+      { room: transcriptTaskRoom(workspaceId, taskId) }
+    );
+  }
 }