Warn on tab close when create-flow module or wizard edits have not been saved.

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

tests/lib/methodCardCustomizeSession.test.ts

@@ -4,6 +4,7 @@ import {
   captureMethodCardCustomizeSnapshot,
   confirmDiscardMethodCardCustomizeSession,
   isMethodCardCustomizeSessionDirty,
+  isMethodCardCustomizeUnloadBlocked,
 } from "../../lib/create/methodCardCustomizeSession";
 
 const HEADER_0 = { title: "", description: "" };
@@ -88,4 +89,24 @@ describe("methodCardCustomizeSession", () => {
     ).toBe(false);
     expect(confirmFn).toHaveBeenCalled();
   });
+
+  it("unload block is false when the modal is closed or snapshot is missing", () => {
+    const snap = captureMethodCardCustomizeSnapshot({ x: 1 }, null, HEADER_0);
+    expect(
+      isMethodCardCustomizeUnloadBlocked(false, snap, { x: 2 }, null, HEADER_0),
+    ).toBe(false);
+    expect(
+      isMethodCardCustomizeUnloadBlocked(true, null, { x: 2 }, null, HEADER_0),
+    ).toBe(false);
+  });
+
+  it("unload block is true only when the open modal is dirty", () => {
+    const snap = captureMethodCardCustomizeSnapshot({ x: 1 }, null, HEADER_0);
+    expect(
+      isMethodCardCustomizeUnloadBlocked(true, snap, { x: 1 }, null, HEADER_0),
+    ).toBe(false);
+    expect(
+      isMethodCardCustomizeUnloadBlocked(true, snap, { x: 2 }, null, HEADER_0),
+    ).toBe(true);
+  });
 });