create logs dir on startup

pkg/actor/disk_storage.go

@@ -147,6 +147,13 @@ func (s *DiskStorage[V]) AppendMutations(id uint64, msg ...proto.Message) error
 		return nil
 	} else {
 		path := s.logPath(id)
+		// Ensure the parent directory exists (e.g. first write to a new PVC mount).
+		// MkdirAll is a no-op when the directory already exists, so it's safe to
+		// call on every AppendMutations without extra stat overhead.
+		if err := os.MkdirAll(s.path, 0755); err != nil {
+			log.Printf("failed to create event log directory %s: %v", s.path, err)
+			return err
+		}
 		fh, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
 		if err != nil {
 			log.Printf("failed to open event log file: %v", err)