feat(#165): Implement BullMQ module setup

Create BullMQ module that shares the existing Valkey connection for job queue processing.

Files Created:
- apps/api/src/bullmq/bullmq.module.ts - Global module configuration
- apps/api/src/bullmq/bullmq.service.ts - Queue management service
- apps/api/src/bullmq/queues.ts - Queue name constants
- apps/api/src/bullmq/index.ts - Barrel exports
- apps/api/src/bullmq/bullmq.service.spec.ts - Unit tests

Files Modified:
- apps/api/src/app.module.ts - Import BullMqModule

Queue Definitions:
- mosaic-jobs (main queue)
- mosaic-jobs-runner (read-only operations)
- mosaic-jobs-weaver (write operations)
- mosaic-jobs-inspector (validation operations)

Implementation:
- Reuses VALKEY_URL from environment (shared connection)
- Follows existing Valkey module patterns
- Includes health check methods
- Proper lifecycle management (init/destroy)
- Queue names use hyphens instead of colons (BullMQ requirement)

Quality Gates:
- Unit tests: 11 passing
- TypeScript: No errors
- ESLint: No violations
- Build: Successful

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/bullmq/bullmq.service.ts

@@ -0,0 +1,186 @@
+import { Injectable, Logger, OnModuleInit, OnModuleDestroy } from "@nestjs/common";
+import { Queue, QueueOptions } from "bullmq";
+import { QUEUE_NAMES, QueueName } from "./queues";
+
+/**
+ * Health status interface for BullMQ
+ */
+export interface BullMqHealthStatus {
+  connected: boolean;
+  queues: Record<string, number>;
+}
+
+/**
+ * BullMqService - Job queue service using BullMQ with Valkey backend
+ *
+ * This service provides job queue operations for the Mosaic Component Architecture:
+ * - Main queue for general purpose jobs
+ * - Runner queue for read-only operations
+ * - Weaver queue for write operations
+ * - Inspector queue for validation operations
+ *
+ * Shares the same Valkey connection used by ValkeyService (VALKEY_URL).
+ */
+@Injectable()
+export class BullMqService implements OnModuleInit, OnModuleDestroy {
+  private readonly logger = new Logger(BullMqService.name);
+  private readonly queues = new Map<string, Queue>();
+
+  async onModuleInit(): Promise<void> {
+    const valkeyUrl = process.env.VALKEY_URL ?? "redis://localhost:6379";
+
+    this.logger.log(`Initializing BullMQ with Valkey at ${valkeyUrl}`);
+
+    // Parse Redis URL for connection options
+    const connectionOptions = this.parseRedisUrl(valkeyUrl);
+
+    const queueOptions: QueueOptions = {
+      connection: connectionOptions,
+      defaultJobOptions: {
+        attempts: 3,
+        backoff: {
+          type: "exponential",
+          delay: 1000,
+        },
+        removeOnComplete: {
+          age: 3600, // Keep completed jobs for 1 hour
+          count: 1000, // Keep last 1000 completed jobs
+        },
+        removeOnFail: {
+          age: 86400, // Keep failed jobs for 24 hours
+        },
+      },
+    };
+
+    // Create all queues
+    await this.createQueue(QUEUE_NAMES.MAIN, queueOptions);
+    await this.createQueue(QUEUE_NAMES.RUNNER, queueOptions);
+    await this.createQueue(QUEUE_NAMES.WEAVER, queueOptions);
+    await this.createQueue(QUEUE_NAMES.INSPECTOR, queueOptions);
+
+    this.logger.log(`BullMQ initialized with ${this.queues.size.toString()} queues`);
+  }
+
+  async onModuleDestroy(): Promise<void> {
+    this.logger.log("Closing BullMQ queues");
+
+    for (const [name, queue] of this.queues.entries()) {
+      await queue.close();
+      this.logger.log(`Queue closed: ${name}`);
+    }
+
+    this.queues.clear();
+  }
+
+  /**
+   * Create a queue with the given name and options
+   */
+  private async createQueue(name: QueueName, options: QueueOptions): Promise<Queue> {
+    const queue = new Queue(name, options);
+
+    // Wait for queue to be ready
+    await queue.waitUntilReady();
+
+    this.queues.set(name, queue);
+    this.logger.log(`Queue created: ${name}`);
+
+    return queue;
+  }
+
+  /**
+   * Get a queue by name
+   */
+  getQueue(name: QueueName): Queue | null {
+    return this.queues.get(name) ?? null;
+  }
+
+  /**
+   * Get all queues
+   */
+  getQueues(): Map<string, Queue> {
+    return this.queues;
+  }
+
+  /**
+   * Add a job to a queue
+   */
+  async addJob(
+    queueName: QueueName,
+    jobName: string,
+    data: unknown,
+    options?: {
+      priority?: number;
+      delay?: number;
+      attempts?: number;
+    }
+  ): Promise<ReturnType<Queue["add"]>> {
+    const queue = this.queues.get(queueName);
+
+    if (!queue) {
+      throw new Error(`Queue not found: ${queueName}`);
+    }
+
+    const job = await queue.add(jobName, data, options);
+    this.logger.log(`Job added to ${queueName}: ${jobName} (id: ${job.id ?? "unknown"})`);
+
+    return job;
+  }
+
+  /**
+   * Health check - verify all queues are connected
+   */
+  async healthCheck(): Promise<boolean> {
+    try {
+      for (const queue of this.queues.values()) {
+        // Check if queue client is connected
+        const client = await queue.client;
+        await client.ping();
+      }
+      return true;
+    } catch (error) {
+      const errorMessage = error instanceof Error ? error.message : String(error);
+      this.logger.error("BullMQ health check failed:", errorMessage);
+      return false;
+    }
+  }
+
+  /**
+   * Get health status with queue counts
+   */
+  async getHealthStatus(): Promise<BullMqHealthStatus> {
+    const connected = await this.healthCheck();
+    const queues: Record<string, number> = {};
+
+    for (const [name, queue] of this.queues.entries()) {
+      try {
+        const count = await queue.count();
+        queues[name] = count;
+      } catch (error) {
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        this.logger.error(`Failed to get count for queue ${name}:`, errorMessage);
+        queues[name] = -1;
+      }
+    }
+
+    return { connected, queues };
+  }
+
+  /**
+   * Parse Redis URL into connection options
+   */
+  private parseRedisUrl(url: string): { host: string; port: number } {
+    try {
+      const parsed = new URL(url);
+      return {
+        host: parsed.hostname,
+        port: parseInt(parsed.port || "6379", 10),
+      };
+    } catch {
+      this.logger.warn(`Failed to parse Redis URL: ${url}, using defaults`);
+      return {
+        host: "localhost",
+        port: 6379,
+      };
+    }
+  }
+}