feat(worker): add index queue and wire Meilisearch indexing after approval

Adds index.queue.ts and index.processor.ts to handle BullMQ indexing jobs,
updates main.ts to create a Meilisearch client, configure the index on startup,
and enqueue index + forward jobs from ApprovalResult after a star reaction.

apps/worker/src/queues/index.queue.ts

@@ -0,0 +1,7 @@
+import { Queue } from 'bullmq';
+import { IndexJobData } from '@tower/types';
+import { parseRedisUrl } from './redis-connection';
+
+export function createIndexQueue(redisUrl: string): Queue<IndexJobData> {
+  return new Queue<IndexJobData>('tower-index', { connection: parseRedisUrl(redisUrl) });
+}