fix(panel): streamline system settings and server creation

Use shared action buttons and default to the login space. Allow staff to save startup-only experience settings while running and request a durable restart through the existing operator flow.

Grant the API PVC list permission needed to detect retained worlds before server creation, and show internal failures with a request ID. Cover permission, maintenance, restart and UI behavior with regression checks.

internal/maintenance/maintenance.go

@@ -90,11 +90,12 @@ const (
 
 // Kinds of holder.
 const (
-	KindMigration = "migration"
-	KindRestore   = "restore"
-	KindBackup    = "backup"
-	KindFileWrite = "file-write"
-	KindExport    = "export"
+	KindMigration   = "migration"
+	KindRestore     = "restore"
+	KindBackup      = "backup"
+	KindFileWrite   = "file-write"
+	KindConfigWrite = "config-write"
+	KindExport      = "export"
 	// KindReap is the reaper archiving an idle world and reclaiming its volume.
 	// It runs no Job: the reaper holds the Annotation itself and rewrites it
 	// well inside Grace for as long as it works on the world.