fix(pipeline): add redis+libretranslate to homelab, make Asynq enqueue errors non-fatal

- homelab/docker-compose.yml: add redis:7-alpine service (port 6379 bound to host
  so Caddy TLS proxy on prod can reach it), add libretranslate service, add
  redis_data and libretranslate_data volumes
- asynqqueue/producer.go: Asynq enqueue failures are now logged as warnings instead
  of returned as errors — PB record already exists so runner picks it up via poll
- backend/main.go: pass logger to NewProducer

Root cause: Redis was not reachable at 192.168.0.109:6379 because the redis
container had no host port binding. Caddy TLS proxy terminates TLS but could
not TCP-connect to the backend Redis.

backend/cmd/backend/main.go

@@ -134,7 +134,7 @@ func run() error {
 		if parseErr != nil {
 			return fmt.Errorf("parse REDIS_ADDR: %w", parseErr)
 		}
-		asynqProducer := asynqqueue.NewProducer(store, redisOpt)
+		asynqProducer := asynqqueue.NewProducer(store, redisOpt, log)
 		defer asynqProducer.Close() //nolint:errcheck
 		producer = asynqProducer
 		log.Info("backend: asynq task dispatch enabled", "addr", cfg.Redis.Addr)