feat: use postgres

mail/internal/worker/command_consumer.go

@@ -304,9 +304,10 @@ func optionalRawString(values map[string]any, key string) string {
 	return value
 }
 
-// Shutdown stops the command consumer within ctx. The consumer uses the
-// shared process Redis client and therefore has no dedicated resources to
-// release here.
+// Shutdown stops the command consumer within ctx. The consumer borrows the
+// shared process Redis client and forcibly closes it during Shutdown so the
+// in-flight blocking XREAD returns immediately; the runtime owns the same
+// client and its cleanupFn is tolerant of ErrClosed.
 func (consumer *CommandConsumer) Shutdown(ctx context.Context) error {
 	if ctx == nil {
 		return errors.New("shutdown command consumer: nil context")
@@ -318,9 +319,10 @@ func (consumer *CommandConsumer) Shutdown(ctx context.Context) error {
 	var err error
 	consumer.closeOnce.Do(func() {
 		if consumer.client != nil {
-			err = consumer.client.Close()
+			if cerr := consumer.client.Close(); cerr != nil && !errors.Is(cerr, redis.ErrClosed) {
+				err = cerr
+			}
 		}
 	})
-
 	return err
 }