feat: page version history improvements (#1925)

* Refactor: use queue for page history

* feat: save multiple version contributors

* display contributor avatars in history list

* fix interval

apps/server/src/collaboration/services/collab-history.service.ts

@@ -0,0 +1,30 @@
+import { Injectable } from '@nestjs/common';
+import { RedisService } from '@nestjs-labs/nestjs-ioredis';
+import type { Redis } from 'ioredis';
+
+const REDIS_KEY_PREFIX = 'history:contributors:';
+
+@Injectable()
+export class CollabHistoryService {
+  private readonly redis: Redis;
+
+  constructor(private readonly redisService: RedisService) {
+    this.redis = this.redisService.getOrThrow();
+  }
+
+  async addContributors(pageId: string, userIds: string[]): Promise<void> {
+    if (userIds.length === 0) return;
+    await this.redis.sadd(REDIS_KEY_PREFIX + pageId, ...userIds);
+  }
+
+  async popContributors(pageId: string): Promise<string[]> {
+    const key = REDIS_KEY_PREFIX + pageId;
+    const count = await this.redis.scard(key);
+    if (count === 0) return [];
+    return await this.redis.spop(key, count);
+  }
+
+  async clearContributors(pageId: string): Promise<void> {
+    await this.redis.del(REDIS_KEY_PREFIX + pageId);
+  }
+}