feat(server): add cron job for session cleanup (#13181)

fix AI-338

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

@@ -0,0 +1,67 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { Cron, CronExpression } from '@nestjs/schedule';
+
+import { JobQueue, OneDay, OnJob } from '../../base';
+import { Models } from '../../models';
+
+declare global {
+  interface Jobs {
+    'copilot.session.cleanupEmptySessions': {};
+    'copilot.session.generateMissingTitles': {};
+  }
+}
+
+const GENERATE_TITLES_BATCH_SIZE = 100;
+
+@Injectable()
+export class CopilotCronJobs {
+  private readonly logger = new Logger(CopilotCronJobs.name);
+
+  constructor(
+    private readonly models: Models,
+    private readonly jobs: JobQueue
+  ) {}
+
+  @Cron(CronExpression.EVERY_DAY_AT_MIDNIGHT)
+  async dailyCleanupJob() {
+    await this.jobs.add(
+      'copilot.session.cleanupEmptySessions',
+      {},
+      { jobId: 'daily-copilot-cleanup-empty-sessions' }
+    );
+
+    await this.jobs.add(
+      'copilot.session.generateMissingTitles',
+      {},
+      { jobId: 'daily-copilot-generate-missing-titles' }
+    );
+  }
+
+  @OnJob('copilot.session.cleanupEmptySessions')
+  async cleanupEmptySessions() {
+    const { removed, cleaned } =
+      await this.models.copilotSession.cleanupEmptySessions(
+        new Date(Date.now() - OneDay)
+      );
+
+    this.logger.log(
+      `Cleanup completed: ${removed} sessions deleted, ${cleaned} sessions marked as deleted`
+    );
+  }
+
+  @OnJob('copilot.session.generateMissingTitles')
+  async generateMissingTitles() {
+    const sessions = await this.models.copilotSession.toBeGenerateTitle(
+      GENERATE_TITLES_BATCH_SIZE
+    );
+
+    for (const session of sessions) {
+      await this.jobs.add('copilot.session.generateTitle', {
+        sessionId: session.id,
+      });
+    }
+    this.logger.log(
+      `Scheduled title generation for ${sessions.length} sessions`
+    );
+  }
+}