feat(core): migrate more pull to realtime (#14936)

#### PR Dependency Tree


* **PR #14936** 👈

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

* **Refactor**
* Consolidated realtime subscription patterns for consistent, more
reliable live updates across comments, notifications, transcription
tasks, and embedding progress.
* Standardized realtime room naming and subscription keys for
deterministic delivery.

* **New Features**
* Introduced a reusable live-query mechanism powering realtime snapshot
+ event workflows used by comments, notifications, transcript tasks, and
embedding progress.

* **Tests**
* Added tests covering live-query behavior and deterministic
subscription key generation.

[![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/14936)
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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

@@ -9,7 +9,10 @@ import {
   OnJob,
   sniffMime,
 } from '../../../base';
-import type { RealtimePublisher } from '../../../core/realtime';
+import {
+  type RealtimePublisher,
+  realtimeTranscriptTaskRoom,
+} from '../../../core/realtime';
 import { Models } from '../../../models';
 import { CopilotAccessPolicy } from '../access';
 import { PromptService } from '../prompt';
@@ -33,10 +36,6 @@ 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;
@@ -468,7 +467,7 @@ export class CopilotTranscriptionService {
       'copilot.transcript.task.changed',
       { workspaceId, taskId },
       { taskId, status, error },
-      { room: transcriptTaskRoom(workspaceId, taskId) }
+      { room: realtimeTranscriptTaskRoom(workspaceId, taskId) }
     );
   }
 }