feat: Redis caching + async queue for LLM scaling (v1.6.0)

- Add async Redis client singleton (redis_client.py) for caching and arq pool
- Add arq job functions (jobs.py) for background LLM processing
- Cache ask/explain LLM responses with TTL (1h ask, 24h explain)
- Add async mode to /api/ask: enqueue job, return job_id, poll /api/jobs/{id}
- Add GET /api/jobs/{job_id} endpoint for job status polling
- Add arq worker service to docker-compose (dev + prod)
- Switch from Redis to Valkey (BSD fork) in Docker Compose
- Add REDIS_URL config setting
- Add tests for cache hit, async mode, and job status

docker-compose.prod.yml

@@ -1,4 +1,19 @@
 services:
+  redis:
+    image: valkey/valkey:8-alpine
+    container_name: aoc-redis
+    restart: always
+    volumes:
+      - redis_data:/data
+    networks:
+      - aoc-internal
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 10s
+      timeout: 3s
+      retries: 5
+      start_period: 5s
+
   mongo:
     image: mongo:7
     container_name: aoc-mongo
@@ -27,9 +42,12 @@ services:
       - .env
     environment:
       MONGO_URI: mongodb://${MONGO_ROOT_USERNAME}:${MONGO_ROOT_PASSWORD}@mongo:27017/
+      REDIS_URL: redis://redis:6379/0
     depends_on:
       mongo:
         condition: service_healthy
+      redis:
+        condition: service_healthy
     networks:
       - aoc-internal
     healthcheck:
@@ -39,6 +57,24 @@ services:
       retries: 3
       start_period: 10s
 
+  worker:
+    image: git.cqre.net/cqrenet/aoc-backend:${AOC_VERSION:-latest}
+    container_name: aoc-worker
+    restart: always
+    env_file:
+      - .env
+    environment:
+      MONGO_URI: mongodb://${MONGO_ROOT_USERNAME}:${MONGO_ROOT_PASSWORD}@mongo:27017/
+      REDIS_URL: redis://redis:6379/0
+    command: ["arq", "jobs.WorkerSettings"]
+    depends_on:
+      redis:
+        condition: service_healthy
+      mongo:
+        condition: service_healthy
+    networks:
+      - aoc-internal
+
   nginx:
     image: nginx:alpine
     container_name: aoc-nginx
@@ -58,6 +94,7 @@ services:
 
 volumes:
   mongo_data:
+  redis_data:
 
 networks:
   aoc-internal: