feat(modal): add cancellable shared runtime

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

assets/js/core/modal-state.js

@@ -0,0 +1,34 @@
+/**
+ * Shared modal state vocabulary.
+ *
+ * @package AKSRT
+ */
+(function (window) {
+  "use strict";
+
+  var statuses = {
+    idle: "idle",
+    loading: "loading",
+    ready: "ready",
+    empty: "empty",
+    submitting: "submitting",
+    success: "success",
+    error: "error",
+    unauthorized: "unauthorized",
+    stale: "stale",
+  };
+
+  function create(kind) {
+    return {
+      kind: String(kind || "generic"),
+      status: statuses.idle,
+      updatedAt: 0,
+      error: null,
+    };
+  }
+
+  window.AksrtModalState = {
+    statuses: statuses,
+    create: create,
+  };
+})(window);