✨ feat(mana-crawler): add web crawler service

NestJS-based web crawler service for structured content extraction.

Features:
- Depth-controlled crawling with URL pattern filtering
- robots.txt compliance
- HTML/PDF/Markdown content extraction
- BullMQ job queue for async processing
- Redis caching layer
- Prometheus metrics

services/mana-crawler/src/db/database.module.ts

@@ -0,0 +1,24 @@
+import { Global, Module } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { getDb } from './connection';
+
+export const DATABASE_CONNECTION = 'DATABASE_CONNECTION';
+
+@Global()
+@Module({
+	providers: [
+		{
+			provide: DATABASE_CONNECTION,
+			useFactory: (configService: ConfigService) => {
+				const databaseUrl = configService.get<string>('database.url');
+				if (!databaseUrl) {
+					throw new Error('DATABASE_URL is not configured');
+				}
+				return getDb(databaseUrl);
+			},
+			inject: [ConfigService],
+		},
+	],
+	exports: [DATABASE_CONNECTION],
+})
+export class DatabaseModule {}