test(ui): migrate suite to the app-shell (state-driven navigation)

- Unit: repoint moved screen imports (lib/screens, lib/game), mock
  $lib/app-nav (appScreen/activeView) instead of $app/navigation, drop the
  removed gameId props, assert screen/view selection.
- e2e: add a dev-only window.__galaxyNav affordance; specs enter a game via
  enterGame(...) instead of a /games/:id URL; URL assertions become content
  assertions (the URL stays /game/); reload uses waitUntil:"commit" (shallow
  routing) and mocks /rpc on game entry.
- Remove the obsolete report scroll-restore test (it relied on a SvelteKit
  route Snapshot that no longer exists); update the missing-membership test
  to the new lobby-redirect+toast behaviour. Fix a stale report.svelte
  docstring.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/frontend/tests/lobby-create.test.ts

@@ -1,7 +1,10 @@
-// Component tests for the create-game form. The lobby API is mocked
+// Component tests for the create-game screen. The lobby API is mocked
 // at module level; the GalaxyClient is replaced with a stub that does
 // nothing (the test only asserts the createGame wrapper is invoked
-// with the right shape).
+// with the right shape). The app-shell navigation store is mocked so
+// cancel and post-submit both resolve to `appScreen.go("lobby")`
+// without running real `pushState` in JSDOM — the single-URL shell has
+// no `/lobby` route.
 
 import "fake-indexeddb/auto";
 import { fireEvent, render, waitFor } from "@testing-library/svelte";
@@ -21,9 +24,13 @@ import { type GalaxyDB, openGalaxyDB } from "../src/platform/store/idb";
 import { IDBCache } from "../src/platform/store/idb-cache";
 import { WebCryptoKeyStore } from "../src/platform/store/webcrypto-keystore";
 
-const gotoSpy = vi.fn<(url: string) => Promise<void>>(async () => {});
-vi.mock("$app/navigation", () => ({
-	goto: (url: string) => gotoSpy(url),
+// The create screen returns to the lobby through `appScreen.go("lobby")`,
+// which internally calls SvelteKit `pushState`. Mock the whole nav
+// module so the spy captures the transition and no real history
+// mutation runs in JSDOM.
+const appScreenGoSpy = vi.fn();
+vi.mock("$lib/app-nav.svelte", () => ({
+	appScreen: { go: (...args: unknown[]) => appScreenGoSpy(...args) },
 }));
 
 const createGameSpy = vi.fn();
@@ -82,7 +89,7 @@ beforeEach(async () => {
 	await session.signIn("device-1");
 	i18n.resetForTests("en");
 	createGameSpy.mockReset();
-	gotoSpy.mockReset();
+	appScreenGoSpy.mockReset();
 });
 
 afterEach(async () => {
@@ -97,11 +104,13 @@ afterEach(async () => {
 	});
 });
 
-async function importCreatePage(): Promise<typeof import("../src/routes/lobby/create/+page.svelte")> {
-	return import("../src/routes/lobby/create/+page.svelte");
+async function importCreatePage(): Promise<
+	typeof import("../src/lib/screens/lobby-create-screen.svelte")
+> {
+	return import("../src/lib/screens/lobby-create-screen.svelte");
 }
 
-describe("lobby/create page", () => {
+describe("lobby/create screen", () => {
 	test("submitting a valid form invokes createGame with the entered values and navigates back", async () => {
 		createGameSpy.mockResolvedValue({
 			gameId: "private-new",
@@ -150,7 +159,7 @@ describe("lobby/create page", () => {
 			expect(input.startGapPlayers).toBe(2);
 			expect(input.targetEngineVersion).toBe("v1");
 			expect(input.enrollmentEndsAt).toBeInstanceOf(Date);
-			expect(gotoSpy).toHaveBeenCalledWith("/lobby");
+			expect(appScreenGoSpy).toHaveBeenCalledWith("lobby");
 		});
 	});
 
@@ -179,7 +188,7 @@ describe("lobby/create page", () => {
 		});
 	});
 
-	test("cancel button navigates back to /lobby without calling the API", async () => {
+	test("cancel button navigates back to the lobby without calling the API", async () => {
 		const Page = (await importCreatePage()).default;
 		const ui = render(Page);
 
@@ -189,7 +198,7 @@ describe("lobby/create page", () => {
 		await fireEvent.click(ui.getByTestId("lobby-create-cancel"));
 
 		await waitFor(() => {
-			expect(gotoSpy).toHaveBeenCalledWith("/lobby");
+			expect(appScreenGoSpy).toHaveBeenCalledWith("lobby");
 			expect(createGameSpy).not.toHaveBeenCalled();
 		});
 	});