fix: chown the storage registry tree to the dokku user

The install trigger created /var/lib/dokku/data/storage-registry and its entries / migrations subdirectories as root with mode 0755, so the dokku user that runs storage:create couldn't write entry JSON files or migration flag files into them. Mirrors what PropertySetup does for config/storage by calling SetPermissions on each registry path. This unblocks the bats coverage that was failing at the first storage:create call.

plugins/storage/triggers.go

@@ -35,6 +35,21 @@ func TriggerInstall() error {
 		return err
 	}
 
+	// The install trigger runs as root; the directories it just made are
+	// root-owned, but the dokku user is the one that runs storage:create
+	// and writes entry / migration-flag files into them.
+	for _, dir := range []string{RegistryDirectory(), EntriesDirectory(), migrationFlagDir()} {
+		if err := os.MkdirAll(dir, 0755); err != nil {
+			return fmt.Errorf("Unable to create %s: %s", dir, err.Error())
+		}
+		if err := common.SetPermissions(common.SetPermissionInput{
+			Filename: dir,
+			Mode:     0755,
+		}); err != nil {
+			return fmt.Errorf("Unable to set permissions on %s: %s", dir, err.Error())
+		}
+	}
+
 	if err := MigrateLegacyMounts(); err != nil {
 		return fmt.Errorf("storage migration failed: %w", err)
 	}