Wire Publish rule from create flow

lib/create/lastPublishedRule.ts

@@ -0,0 +1,50 @@
+/**
+ * Bridges final-review → completed without query strings.
+ * Replace with GET /api/rules/[id] (CR-81) when public rule fetch exists.
+ */
+export const CREATE_FLOW_LAST_PUBLISHED_KEY = "createFlow.lastPublished";
+
+export type StoredLastPublishedRule = {
+  id: string;
+  title: string;
+  summary?: string | null;
+  document: Record<string, unknown>;
+};
+
+export function writeLastPublishedRule(data: StoredLastPublishedRule): void {
+  if (typeof sessionStorage === "undefined") return;
+  sessionStorage.setItem(CREATE_FLOW_LAST_PUBLISHED_KEY, JSON.stringify(data));
+}
+
+export function readLastPublishedRule(): StoredLastPublishedRule | null {
+  if (typeof sessionStorage === "undefined") return null;
+  const raw = sessionStorage.getItem(CREATE_FLOW_LAST_PUBLISHED_KEY);
+  if (!raw) return null;
+  try {
+    const parsed = JSON.parse(raw) as unknown;
+    if (!parsed || typeof parsed !== "object") return null;
+    const o = parsed as Record<string, unknown>;
+    if (typeof o.id !== "string" || typeof o.title !== "string") return null;
+    const doc = o.document;
+    if (doc === null || typeof doc !== "object" || Array.isArray(doc)) {
+      return null;
+    }
+    const summaryVal = o.summary;
+    let summary: string | null | undefined;
+    if (typeof summaryVal === "string") {
+      summary = summaryVal;
+    } else if (summaryVal === null) {
+      summary = null;
+    } else {
+      summary = undefined;
+    }
+    return {
+      id: o.id,
+      title: o.title,
+      summary,
+      document: doc as Record<string, unknown>,
+    };
+  } catch {
+    return null;
+  }
+}