Fix TS build: add isNewPlayer to GamePage test mocks

The UsePlayerServiceReturn interface gained a required isNewPlayer
property but the existing GamePage.test.tsx and GamePage.integration.test.tsx
mock objects were not updated, causing tsc -b to fail in CI.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: xenobiasoft

src/frontend/Sudoku.React/src/pages/GamePage.integration.test.tsx

@@ -44,6 +44,7 @@ beforeEach(() => {
     playerAlias: 'test-player',
     profileId: null,
     isInitialized: true,
+    isNewPlayer: false,
     isLoading: false,
     error: null,
     initializePlayer: vi.fn(),
@@ -151,6 +152,7 @@ describe('GamePage - New Architecture', () => {
       playerAlias: null,
       profileId: null,
       isInitialized: false,
+      isNewPlayer: true,
       isLoading: false,
       error: null,
       initializePlayer: vi.fn(),

src/frontend/Sudoku.React/src/pages/GamePage.test.tsx

@@ -64,6 +64,7 @@ beforeEach(() => {
     playerAlias: 'test-player',
     profileId: null,
     isInitialized: true,
+    isNewPlayer: false,
     isLoading: false,
     error: null,
     initializePlayer: vi.fn(),
@@ -140,6 +141,7 @@ describe('GamePage - loading', () => {
       playerAlias: null,
       profileId: null,
       isInitialized: false,
+      isNewPlayer: true,
       isLoading: true,
       error: null,
       initializePlayer: vi.fn(),
@@ -156,6 +158,7 @@ describe('GamePage - loading', () => {
       isInitialized: false,
       isLoading: false,
       error: null,
+      isNewPlayer: true,
       initializePlayer: vi.fn(),
       clearPlayer: vi.fn(),
     });
@@ -168,6 +171,7 @@ describe('GamePage - loading', () => {
       playerAlias: null,
       profileId: null,
       isInitialized: true,
+      isNewPlayer: false,
       isLoading: false,
       error: 'Failed to initialize player',
       initializePlayer: vi.fn(),
@@ -268,6 +272,7 @@ describe('GamePage - after load', () => {
       playerAlias: null,
       profileId: null,
       isInitialized: false,
+      isNewPlayer: true,
       isLoading: false,
       error: null,
       initializePlayer: vi.fn(),