feat(valkey): migrate redis to valkey and fix updater custom prefix selection

Replace redis:7-alpine with valkey:8.0-alpine and configure MaintNotificationsConfig ModeDisabled to suppress handshake warnings on Valkey. Resolve updater bug by dynamically matching custom repository asset name prefixes like PixezSync.

docker-compose.yml

@@ -41,15 +41,15 @@ services:
       start_period: 10s
 
   redis:
-    image: redis:7-alpine
+    image: valkey/valkey:8.0-alpine
     restart: unless-stopped
-    command: ["redis-server", "--appendonly", "yes"]
+    command: ["valkey-server", "--appendonly", "yes"]
     ports:
       - "${REDIS_PORT:-6379}:6379"
     volumes:
-      - ./data/redis_data:/data
+      - ./data/valkey:/data
     healthcheck:
-      test: ["CMD", "redis-cli", "ping"]
+      test: ["CMD", "valkey-cli", "ping"]
       interval: 10s
       timeout: 5s
       retries: 5