新增「原版与二创对比」页与路由登记（含 nginx×3 + Pingora allowlist）

- 新增路由 /games/compare（stage game-compare）：STAGE_ROUTE_ENTRIES + SelectionStage 类型 + 壳层 lazy 引入/导航回调/渲染分支 + 页面标题，四处同批登记
- 三份 nginx SPA allowlist（deploy/nginx/genarrative.conf、deploy/nginx/genarrative-dev-http.conf、deploy/container/nginx.conf）与 Pingora MAIN_SPA_PATHS 同步放行 /games/compare（保持既有排序）：check:nginx-spa-routes 18 SPA routes、check:pingora-route-parity 均绿
- 对比页左右两侧各自取数与降级：任一侧不可读（不存在/未公开/已软删除）或没有可玩版本时只降级那一侧，另一侧照常；显示标题、作者与代际；桌面左右并排、窄屏上下堆叠
- iframe 复用游玩页同一份嵌入：抽出 GamePlayFrame（sandbox=allow-scripts、allow=fullscreen、referrerPolicy=no-referrer、.game-player-frame），游玩页改为渲染它，不再存在第二套嵌入逻辑
- 入口：二创作品详情页在存在父作品时给出「与原版对比」；族谱节点仅在其父作品可见时给出同一入口
- 测试：对比页两侧渲染与 iframe 复用属性、单侧降级后另一侧照常；详情页入口（有/无父作品）；族谱节点入口（父可见才出现）；路由与标题登记；壳层「族谱节点→对比页」导航与对比 stage 渲染
- 顺手：按 eslint 自动修复两个文件的 import 排序

src/components/platform-entry/PlatformEntryActiveFlowShell.test.tsx

@@ -1429,4 +1429,68 @@ describe('创作族谱', () => {
       path: '/games/lineage?id=game-root&from=game-1',
     });
   });
+
+  it('族谱节点可打开「原版与二创对比」', async () => {
+    window.history.replaceState(null, '', '/games/lineage?id=game-root');
+    gameDistributionMock.getGameLineage.mockResolvedValue(lineageTree);
+    const setSelectionStage = vi.fn();
+
+    render(
+      <PlatformEntryFlowShellImpl
+        selectionStage="game-lineage"
+        setSelectionStage={setSelectionStage}
+      />,
+    );
+
+    fireEvent.click(await screen.findByRole('button', { name: '与原版对比' }));
+    expect(setSelectionStage).toHaveBeenCalledWith('game-compare', {
+      path: '/games/compare?left=game-root&right=game-leaf',
+    });
+  });
+
+  it('对比页按 left/right 参数左右渲染两侧作品', async () => {
+    window.history.replaceState(
+      null,
+      '',
+      '/games/compare?left=game-1&right=game-2',
+    );
+    gameDistributionMock.getGame.mockImplementation((gameId: string) =>
+      Promise.resolve({
+        id: gameId,
+        title: `对比作品 ${gameId}`,
+        summary: '并排对比',
+        description: '',
+        category: '动作',
+        tags: [],
+        coverColor: '#d77a51',
+        icon: '✦',
+        author: { id: 'author-1', name: '测试作者' },
+        deviceSupport: { desktop: true, mobile: true, touch: true },
+        status: 'published',
+        currentVersion: {
+          id: `version-${gameId}`,
+          version: '1.0.0',
+          entryUrl: `https://play.example.test/releases/${gameId}/index.html`,
+          sha256: 'sha256',
+          publishedAt: '2026-09-18T00:00:00.000Z',
+          controls: ['键盘'],
+        },
+        playCount: 1,
+        createdAt: '2026-09-18T00:00:00.000Z',
+      }),
+    );
+
+    render(
+      <PlatformEntryFlowShellImpl
+        selectionStage="game-compare"
+        setSelectionStage={vi.fn()}
+      />,
+    );
+
+    expect(await screen.findByText('对比作品 game-1')).toBeTruthy();
+    expect(screen.getByText('对比作品 game-2')).toBeTruthy();
+    expect(document.querySelectorAll('iframe.game-player-frame')).toHaveLength(
+      2,
+    );
+  });
 });