feat(plugin): add SCUM ownership migration foundation

platform/domain/resources.go

@@ -312,10 +312,20 @@ type GamePluginPage struct {
 	Key           string
 	Title         string
 	Path          string
+	Bundle         PluginPageBundle
 	Permissions   []string
 	BridgeActions []string
 }
 
+// PluginPageBundle identifies an installed plugin-owned page module. The host
+// validates this declaration before loading a bundle and never selects a game
+// page by plugin ID.
+type PluginPageBundle struct {
+	Key             string
+	Version         string
+	IntegritySHA256 string
+}
+
 // PluginFileWorkspace is a bounded, logical catalog for a plugin-owned files
 // workbench. Keys are logical identifiers, never host paths.
 type PluginFileWorkspace struct {