fix: skip Redis connection in test mode — prevents CI hang

The top-level await redisClient.connect() in redis-client.js was
blocking module import when no Redis server is available (CI env).
Add NODE_ENV guard + reconnect strategy with max retries.

apps/backend/redis-client.js

@@ -4,7 +4,11 @@ import { createClient } from 'redis';
 const redisClient = createClient({
   socket: {
     host: process.env.REDIS_HOST || 'localhost',
-    port: process.env.REDIS_PORT || 6379
+    port: process.env.REDIS_PORT || 6379,
+    reconnectStrategy: (retries) => {
+      if (retries > 10) return new Error('Redis max retries reached');
+      return Math.min(retries * 100, 3000);
+    }
   },
   password: process.env.REDIS_PASSWORD || undefined
 });
@@ -19,7 +23,9 @@ redisClient.on('connect', () => {
   console.log('✅ Connected to Redis');
 });
 
-// Connect to Redis
+// Connect to Redis — skip in test (services are mocked) or when REDIS_URL is unset
+if (process.env.NODE_ENV !== 'test') {
   await redisClient.connect();
+}
 
 export default redisClient;