test(ui): isolate overlay lifecycle in layout navigation tests

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/src/components/Layout.test.tsx

@@ -117,6 +117,12 @@ vi.mock("./PropertiesPanel", () => ({
   PropertiesPanel: () => null,
 }));
 
+// Overlay account/company lifecycle has its own integration test. These tests
+// exercise route navigation with intentionally minimal context providers.
+vi.mock("./PluginAppShellOverlays", () => ({
+  PluginAppShellOverlays: () => null,
+}));
+
 vi.mock("./CommandPalette", () => ({
   CommandPalette: () => null,
 }));