Let guests keep a published rule via Save & Exit and a post-finalize sign-in prompt.

Email is optional so they can continue without saving; skip from Save & Exit leaves the flow instead of returning to completed.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/create/pendingKeepRuleLogin.ts

@@ -0,0 +1,22 @@
+/**
+ * Guest finalize → `/create/completed` keep-this-rule login. Stored in
+ * sessionStorage so the prompt survives create-layout remounts and is not
+ * tied to the Finalize click (that click would otherwise dismiss the overlay).
+ */
+export const CREATE_FLOW_PENDING_KEEP_RULE_LOGIN_KEY =
+  "createFlow.pendingKeepRuleLogin";
+
+export function writePendingKeepRuleLogin(): void {
+  if (typeof sessionStorage === "undefined") return;
+  sessionStorage.setItem(CREATE_FLOW_PENDING_KEEP_RULE_LOGIN_KEY, "1");
+}
+
+export function hasPendingKeepRuleLogin(): boolean {
+  if (typeof sessionStorage === "undefined") return false;
+  return sessionStorage.getItem(CREATE_FLOW_PENDING_KEEP_RULE_LOGIN_KEY) === "1";
+}
+
+export function clearPendingKeepRuleLogin(): void {
+  if (typeof sessionStorage === "undefined") return;
+  sessionStorage.removeItem(CREATE_FLOW_PENDING_KEEP_RULE_LOGIN_KEY);
+}