网页端共创主题：共创 Tab + 主题页（逐根内嵌作品树）+ 详情页主题入口 + 网关清单

- 客户端：新增 listThemes（游标分页，读 nextCursor）与 getTheme（404 由页面渲染成降级态）；getGame 的返回类型增量 themes（匿名也返回；无主题时是空数组而不是缺键）
- 共创 Tab：广场页新增「游戏 / 共创」页签，复用既有 game-category-tabs 结构与类名，切到 /games/themes
- 主题列表页 GameThemesPage：卡片展示 name / summary / badge / memberCount；只有 nextCursor 非空才渲染「加载更多」并在点击时追加；空态与失败重试照既有写法
- 主题页 GameThemePage：标题 / 简介 / 角标 + 成员根清单；**逐根内嵌渲染作品树**——直接复用族谱页（GameLineagePage 新增 embedded 变体，只隐藏页面外壳：返回按钮 / 页头 / 脚注），树查询、可见性过滤、稳定排序与截断全部走 M3 那一份实现，不新建第二套树查询或树渲染（每根一次 /lineage 的 N+1 是技术方案 §3.10.4 已接受的取舍）；已发布但可见成员为空 → 明确空态而不是错误；主题不存在 / 未发布 → 错误态
- 详情页：共创信息卡渲染所属主题角标（点击进主题页），第 N 代作品同样可见（服务端按根反查）；无主题时不渲染空容器
- 路由登记：新增 /games/themes 与 /games/theme（详情用 ?id=），四处同批登记（STAGE_ROUTE_ENTRIES + SelectionStage 类型 + 壳层 lazy/回调/渲染分支 + 页面标题），并同步三份 nginx SPA allowlist 与 Pingora MAIN_SPA_PATHS：check:nginx-spa-routes（20 SPA routes / 3 模板）与 check:pingora-route-parity 均绿
- 测试：主题列表三例（渲染与卡片跳转 / 有游标时的加载更多与追加 / 空态与失败重试）、主题页三例（逐根两棵树且复用 lineage 查询 + 全屏入口参数 / 空成员空态 / 404 错误态）、详情页主题入口两例（渲染并可跳转 / 无主题不渲染容器）、路由与标题登记断言、壳层三例（页签切换 / 列表进主题页 / 主题页按 ?id= 渲染并复用族谱查询）

src/components/game-distribution/GameDetailPage.tsx

@@ -66,6 +66,8 @@ type GameDetailPageProps = {
    * 只有存在父作品的二创作品才渲染该入口。
    */
   onOpenCompare?: (leftGameId: string, rightGameId: string) => void;
+  /** 打开所属共创主题页（`/games/theme?id=<themeId>`）。 */
+  onOpenTheme?: (themeId: string) => void;
   /**
    * 作者视角：走 `GET /my-games/{gameId}` 读取自己名下作品。
    *
@@ -137,6 +139,7 @@ export function GameDetailPage({
   onOpenLineage,
   onOpenCreator,
   onOpenCompare,
+  onOpenTheme,
   ownerView = false,
 }: GameDetailPageProps) {
   const authUi = useAuthUi();
@@ -297,6 +300,7 @@ export function GameDetailPage({
       onPlay={onPlay}
       onOpenLineage={onOpenLineage}
       onOpenCompare={onOpenCompare}
+      onOpenTheme={onOpenTheme}
       isAuthenticated={Boolean(authUi?.user)}
     />
   );
@@ -316,6 +320,7 @@ function GameDetailContent({
   onOpenLineage,
   onOpenCreator,
   onOpenCompare,
+  onOpenTheme,
 }: {
   game: GameDistributionGame;
   ownerView: boolean;
@@ -331,6 +336,7 @@ function GameDetailContent({
   onOpenLineage?: (rootGameId: string, fromGameId?: string) => void;
   onOpenCreator?: (id: string) => void;
   onOpenCompare?: (leftGameId: string, rightGameId: string) => void;
+  onOpenTheme?: (themeId: string) => void;
 }) {
   /**
    * 只有已公开作品才有公开评价/评分投影；审核中、审核未通过、未公开、已下架
@@ -366,6 +372,8 @@ function GameDetailContent({
   );
   const lineage = game.lineage ?? null;
   const forkCount = game.forkCount ?? 0;
+  // 所属共创主题：匿名也返回；没有主题时是空数组（不渲染空容器）。
+  const themes = game.themes ?? [];
   // Fork 的主路径是唤起客户端；只有「没失焦（没客户端接手）」或「平台不可能唤起」才降级成
   // 「复制作品 ID / 链接 → 到客户端粘贴」。降级面板同理只在降级时出现。
   const [isForkPanelOpen, setIsForkPanelOpen] = useState(false);
@@ -603,6 +611,29 @@ function GameDetailContent({
                     与原版对比
                   </button>
                 ) : null}
+                {onOpenTheme && themes.length > 0 ? (
+                  /*
+                    所属共创主题入口：服务端按作品的**根**反查，所以第 N 代作品也会有值；
+                    没有所属主题时是空数组（不是缺键），这里不渲染空容器。
+                  */
+                  <span className="game-fork-theme-list">
+                    {themes.map((theme) => (
+                      <button
+                        key={theme.themeId}
+                        type="button"
+                        className="game-fork-theme-link"
+                        onClick={() => onOpenTheme(theme.themeId)}
+                      >
+                        {theme.badge ? (
+                          <span className="game-fork-theme-badge">
+                            {theme.badge}
+                          </span>
+                        ) : null}
+                        {theme.name}
+                      </button>
+                    ))}
+                  </span>
+                ) : null}
                 {canRemix ? (
                   /*
                     Fork 入口：服务端取件通道要求 Bearer + 已公开 + 授权非禁止。

src/components/game-distribution/GameDistributionPages.test.tsx

@@ -15,6 +15,7 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import type { GameDistributionVersionStatus } from '../../../packages/shared/src/contracts/gameDistribution';
 import type {
   GameDistributionGame,
+  GameDistributionGameWithCollection,
   GameDistributionLineageNode,
   GameDistributionMyGame,
   GameDistributionVersionStatusEntry,
@@ -26,10 +27,14 @@ import { FORK_LAUNCH_FALLBACK_DELAY_MS } from './gameForkProtocol';
 import { GameGalleryPage } from './GameGalleryPage';
 import { GameLineagePage } from './GameLineagePage';
 import { GamePlayPage } from './GamePlayPage';
+import { GameThemePage } from './GameThemePage';
+import { GameThemesPage } from './GameThemesPage';
 import { resolveNonPublicCoverLabel } from './gameVersionHistoryModel';
 
 const listGamesMock = vi.hoisted(() => vi.fn());
 const setGameCollectionMock = vi.hoisted(() => vi.fn());
+const listThemesMock = vi.hoisted(() => vi.fn());
+const getThemeMock = vi.hoisted(() => vi.fn());
 const getGameMock = vi.hoisted(() => vi.fn());
 const getGameLineageMock = vi.hoisted(() => vi.fn());
 const getMyGameMock = vi.hoisted(() => vi.fn());
@@ -55,6 +60,8 @@ vi.mock('../../services/creatorProfileClient', async (original) => ({
 vi.mock('../../services/gameDistributionClient', () => ({
   listGames: listGamesMock,
   setGameCollection: setGameCollectionMock,
+  listThemes: listThemesMock,
+  getTheme: getThemeMock,
   getGame: getGameMock,
   getGameLineage: getGameLineageMock,
   getMyGame: getMyGameMock,
@@ -121,8 +128,8 @@ function deferred<T>() {
 }
 
 function createGame(
-  overrides: Partial<GameDistributionGame> = {},
-): GameDistributionGame {
+  overrides: Partial<GameDistributionGameWithCollection> = {},
+): GameDistributionGameWithCollection {
   return {
     id: 'game-1',
     title: '星轨防线',
@@ -182,6 +189,10 @@ beforeEach(() => {
   openForkProtocolMock.mockReset();
   setGameCollectionMock.mockReset();
   setGameCollectionMock.mockResolvedValue({ collected: true });
+  listThemesMock.mockReset();
+  listThemesMock.mockResolvedValue({ themes: [], nextCursor: null });
+  getThemeMock.mockReset();
+  getThemeMock.mockResolvedValue(null);
   setCreatorViewer(null);
   getCreatorRelationshipMock.mockResolvedValue({
     relationship: { isSelf: false, isFollowing: false, isFollowedBy: false },
@@ -1688,6 +1699,257 @@ describe('GameComparePage', () => {
   });
 });
 
+describe('GameThemesPage', () => {
+  it('渲染主题卡片（名称 / 角标 / 可见成员数）并可进入主题页', async () => {
+    listThemesMock.mockResolvedValue({
+      themes: [
+        {
+          themeId: 'theme-1',
+          name: '精选共创',
+          summary: '运营精选的共创主题',
+          badge: '精选',
+          memberCount: 2,
+        },
+      ],
+      nextCursor: null,
+    });
+    const onOpenTheme = vi.fn();
+    render(
+      <GameThemesPage
+        onBack={vi.fn()}
+        onOpenGallery={vi.fn()}
+        onOpenTheme={onOpenTheme}
+      />,
+    );
+
+    expect(await screen.findByText('精选共创')).toBeTruthy();
+    expect(screen.getByText('精选')).toBeTruthy();
+    expect(screen.getByText('2 棵作品树')).toBeTruthy();
+    // 末页 nextCursor 为 null：不渲染「加载更多」。
+    expect(screen.queryByRole('button', { name: '加载更多' })).toBeNull();
+
+    fireEvent.click(screen.getByRole('button', { name: /精选共创/u }));
+    expect(onOpenTheme).toHaveBeenCalledWith('theme-1');
+  });
+
+  it('有 nextCursor 时渲染「加载更多」并用游标追加下一页', async () => {
+    listThemesMock
+      .mockResolvedValueOnce({
+        themes: [
+          {
+            themeId: 'theme-1',
+            name: '第一页主题',
+            summary: '',
+            badge: '',
+            memberCount: 1,
+          },
+        ],
+        nextCursor: '100:theme-1',
+      })
+      .mockResolvedValueOnce({
+        themes: [
+          {
+            themeId: 'theme-2',
+            name: '第二页主题',
+            summary: '',
+            badge: '',
+            memberCount: 3,
+          },
+        ],
+        nextCursor: null,
+      });
+    render(
+      <GameThemesPage
+        onBack={vi.fn()}
+        onOpenGallery={vi.fn()}
+        onOpenTheme={vi.fn()}
+      />,
+    );
+
+    fireEvent.click(await screen.findByRole('button', { name: '加载更多' }));
+    await waitFor(() =>
+      expect(listThemesMock).toHaveBeenLastCalledWith('100:theme-1'),
+    );
+    expect(await screen.findByText('第二页主题')).toBeTruthy();
+    // 追加而不是替换。
+    expect(screen.getByText('第一页主题')).toBeTruthy();
+    expect(screen.queryByRole('button', { name: '加载更多' })).toBeNull();
+  });
+
+  it('没有主题时给出空态，失败时给出错误与重试', async () => {
+    listThemesMock.mockResolvedValueOnce({ themes: [], nextCursor: null });
+    render(
+      <GameThemesPage
+        onBack={vi.fn()}
+        onOpenGallery={vi.fn()}
+        onOpenTheme={vi.fn()}
+      />,
+    );
+    expect(
+      await screen.findByText('还没有已发布的共创主题，稍后再来看看。'),
+    ).toBeTruthy();
+
+    cleanup();
+    listThemesMock.mockRejectedValueOnce(new Error('网络错误'));
+    render(
+      <GameThemesPage
+        onBack={vi.fn()}
+        onOpenGallery={vi.fn()}
+        onOpenTheme={vi.fn()}
+      />,
+    );
+    expect(await screen.findByText('网络错误')).toBeTruthy();
+    expect(screen.getByRole('button', { name: '重试' })).toBeTruthy();
+  });
+});
+
+describe('GameThemePage', () => {
+  const rootGame = (id: string, title: string) =>
+    createGame({
+      id,
+      title,
+      lineage: {
+        generation: 0,
+        rootGameId: id,
+        rootTitle: title,
+        parentGameId: id,
+        parentTitle: title,
+        parentAuthorName: '原作者',
+      },
+    });
+
+  it('渲染主题头与逐根的内嵌作品树（复用族谱页）', async () => {
+    getThemeMock.mockResolvedValue({
+      themeId: 'theme-1',
+      name: '精选共创',
+      summary: '运营精选的共创主题',
+      badge: '精选',
+      memberCount: 2,
+      roots: [rootGame('game-root-1', '根一'), rootGame('game-root-2', '根二')],
+    });
+    getGameLineageMock.mockImplementation((rootGameId: string) =>
+      Promise.resolve({
+        rootGameId,
+        root: createLineageNode({
+          gameId: rootGameId,
+          title: `树 ${rootGameId}`,
+          generation: 0,
+          parentGameId: null,
+        }),
+        nodes: [
+          createLineageNode({
+            gameId: rootGameId,
+            title: `树 ${rootGameId}`,
+            generation: 0,
+            parentGameId: null,
+          }),
+        ],
+        truncated: false,
+      }),
+    );
+    const onOpenLineage = vi.fn();
+    render(
+      <GameThemePage
+        themeId="theme-1"
+        onBack={vi.fn()}
+        onOpenDetail={vi.fn()}
+        onOpenLineage={onOpenLineage}
+      />,
+    );
+
+    expect(await screen.findByText('精选共创')).toBeTruthy();
+    expect(screen.getByText('运营精选的共创主题')).toBeTruthy();
+    // 两个根各内嵌一棵树：树数据来自同一个 `/lineage` 查询。
+    expect(await screen.findByText('树 game-root-1')).toBeTruthy();
+    expect(screen.getByText('树 game-root-2')).toBeTruthy();
+    await waitFor(() => expect(getGameLineageMock).toHaveBeenCalledTimes(2));
+    expect(getGameLineageMock).toHaveBeenCalledWith('game-root-1');
+    expect(getGameLineageMock).toHaveBeenCalledWith('game-root-2');
+    // 内嵌模式不渲染族谱页外壳（页头/返回按钮），但保留「全屏查看」入口。
+    expect(screen.getAllByRole('button', { name: '全屏查看族谱' })).toHaveLength(
+      2,
+    );
+    fireEvent.click(
+      screen.getAllByRole('button', { name: '全屏查看族谱' })[0]!,
+    );
+    expect(onOpenLineage).toHaveBeenCalledWith('game-root-1', 'game-root-1');
+  });
+
+  it('已发布但没有可见成员时给出空态而不是错误', async () => {
+    getThemeMock.mockResolvedValue({
+      themeId: 'theme-2',
+      name: '空主题',
+      summary: '',
+      badge: '',
+      memberCount: 0,
+      roots: [],
+    });
+    render(
+      <GameThemePage
+        themeId="theme-2"
+        onBack={vi.fn()}
+        onOpenDetail={vi.fn()}
+      />,
+    );
+
+    expect(
+      await screen.findByText('这个主题还没有可展示的作品树。'),
+    ).toBeTruthy();
+    expect(screen.queryByRole('button', { name: '重试' })).toBeNull();
+  });
+
+  it('主题不存在或未发布时走错误态（服务端 404 不返回空壳）', async () => {
+    getThemeMock.mockRejectedValueOnce(new Error('主题不存在'));
+    render(
+      <GameThemePage
+        themeId="theme-missing"
+        onBack={vi.fn()}
+        onOpenDetail={vi.fn()}
+      />,
+    );
+
+    expect(await screen.findByText('主题不存在')).toBeTruthy();
+    expect(screen.getByRole('button', { name: '重试' })).toBeTruthy();
+  });
+});
+
+describe('GameDetailPage 共创主题入口', () => {
+  it('渲染所属共创主题角标并可进入主题页', async () => {
+    getGameMock.mockResolvedValueOnce(
+      createGame({
+        themes: [{ themeId: 'theme-1', name: '精选共创', badge: '精选' }],
+      }),
+    );
+    const onOpenTheme = vi.fn();
+    render(
+      <GameDetailPage
+        gameId="game-1"
+        onBack={vi.fn()}
+        onPlay={vi.fn()}
+        onOpenTheme={onOpenTheme}
+      />,
+    );
+
+    fireEvent.click(await screen.findByRole('button', { name: /精选共创/u }));
+    expect(onOpenTheme).toHaveBeenCalledWith('theme-1');
+  });
+
+  it('没有所属主题时不渲染主题容器（空数组不是缺键）', async () => {
+    getGameMock.mockResolvedValueOnce(createGame({ themes: [] }));
+    render(
+      <GameDetailPage
+        gameId="game-1"
+        onBack={vi.fn()}
+        onPlay={vi.fn()}
+        onOpenTheme={vi.fn()}
+      />,
+    );
+
+    await screen.findByRole('heading', { name: '星轨防线' });
+    expect(document.querySelector('.game-fork-theme-list')).toBeNull();
+  });
+});
+
 describe('GameDetailPage 收藏按钮', () => {
   it('可判定为已收藏时显示「已收藏」，点击取消收藏', async () => {
     getGameMock.mockResolvedValueOnce(createGame({ collected: true }));

src/components/game-distribution/GameGalleryPage.tsx

@@ -35,6 +35,8 @@ type GameGalleryPageProps = {
   onOpenDetail: (gameId: string) => void;
   onOpenMyGames?: () => void;
   onOpenPublish?: () => void;
+  /** 切到「共创」页签（`/games/themes`）；缺失时不渲染该页签。 */
+  onOpenThemes?: () => void;
 };
 
 export function GameGalleryPage({
@@ -42,6 +44,7 @@ export function GameGalleryPage({
   onOpenDetail,
   onOpenMyGames,
   onOpenPublish,
+  onOpenThemes,
 }: GameGalleryPageProps) {
   const initialFiltersRef = useRef<GameGalleryFilters | null>(null);
   if (initialFiltersRef.current === null) {
@@ -276,6 +279,27 @@ export function GameGalleryPage({
           </label>
         </div>
       </div>
+      {onOpenThemes ? (
+        <div className="game-category-tabs" role="tablist" aria-label="游戏区">
+          <button
+            type="button"
+            role="tab"
+            aria-selected
+            className="game-category-tab game-category-tab--active"
+          >
+            游戏
+          </button>
+          <button
+            type="button"
+            role="tab"
+            aria-selected={false}
+            className="game-category-tab"
+            onClick={onOpenThemes}
+          >
+            共创
+          </button>
+        </div>
+      ) : null}
       <div className="game-category-tabs" role="tablist" aria-label="游戏分类">
         {CATEGORIES.map((item) => (
           <button

src/components/game-distribution/GameLineagePage.tsx

@@ -24,6 +24,11 @@ type GameLineagePageProps = {
   onOpenDetail: (gameId: string) => void;
   /** 打开「原版与二创对比」；参数是原版（父作品）与二创（该节点）。 */
   onOpenCompare?: (leftGameId: string, rightGameId: string) => void;
+  /**
+   * 内嵌模式：隐藏页面外壳（返回按钮 / 页头 / 脚注），只渲染树本身。
+   * 供主题页逐根渲染多棵树复用同一份树查询与渲染（不新建第二套树逻辑）。
+   */
+  embedded?: boolean;
 };
 
 /**
@@ -122,6 +127,7 @@ export function GameLineagePage({
   onBack,
   onOpenDetail,
   onOpenCompare,
+  embedded = false,
 }: GameLineagePageProps) {
   const normalizedRootId = rootGameId?.trim() ?? '';
   const [lineage, setLineage] = useState<GameDistributionLineageResponse | null>(
@@ -172,27 +178,33 @@ export function GameLineagePage({
   const rootTitle = lineage?.root?.title?.trim() ?? '';
 
   return (
-    <div className="game-page game-lineage-page">
-      <button type="button" className="game-back-button" onClick={onBack}>
-        <ArrowLeft /> 返回
-      </button>
-      <div className="game-toolbar">
-        <div className="game-toolbar__title">
-          <span className="game-eyebrow">创作族谱</span>
-          <h2>{rootTitle || '创作族谱'}</h2>
+    <div
+      className={`game-page game-lineage-page${embedded ? ' game-lineage-page--embedded' : ''}`}
+    >
+      {embedded ? null : (
+        <button type="button" className="game-back-button" onClick={onBack}>
+          <ArrowLeft /> 返回
+        </button>
+      )}
+      {embedded ? null : (
+        <div className="game-toolbar">
+          <div className="game-toolbar__title">
+            <span className="game-eyebrow">创作族谱</span>
+            <h2>{rootTitle || '创作族谱'}</h2>
+          </div>
+          {normalizedRootId ? (
+            <PlatformActionButton
+              tone="secondary"
+              size="sm"
+              shape="pill"
+              onClick={() => void loadLineage()}
+              disabled={isLoading}
+            >
+              <RefreshCcw aria-hidden="true" /> 刷新
+            </PlatformActionButton>
+          ) : null}
         </div>
-        {normalizedRootId ? (
-          <PlatformActionButton
-            tone="secondary"
-            size="sm"
-            shape="pill"
-            onClick={() => void loadLineage()}
-            disabled={isLoading}
-          >
-            <RefreshCcw aria-hidden="true" /> 刷新
-          </PlatformActionButton>
-        ) : null}
-      </div>
+      )}
 
       {!normalizedRootId ? (
         <PlatformStatusMessage tone="error" surface="platform">
@@ -281,9 +293,11 @@ export function GameLineagePage({
         </>
       ) : null}
 
-      <p className="game-detail-footnote">
-        族谱只展示已公开的作品；已删除或未公开的来源作品会标注为「原作品已不可用」。
-      </p>
+      {embedded ? null : (
+        <p className="game-detail-footnote">
+          族谱只展示已公开的作品；已删除或未公开的来源作品会标注为「原作品已不可用」。
+        </p>
+      )}
     </div>
   );
 }

src/components/game-distribution/GameThemePage.tsx

@@ -0,0 +1,220 @@
+import './gameDistribution.css';
+
+import { ArrowLeft, RefreshCcw } from 'lucide-react';
+import { useCallback, useEffect, useState } from 'react';
+
+import {
+  type GameDistributionThemeDetail,
+  getTheme,
+} from '../../services/gameDistributionClient';
+import { PlatformActionButton } from '../common/PlatformActionButton';
+import { PlatformEmptyState } from '../common/PlatformEmptyState';
+import { PlatformStatusMessage } from '../common/PlatformStatusMessage';
+import { GameLineagePage } from './GameLineagePage';
+import { useGameAuthorDisplayName } from './useGameAuthorName';
+
+type GameThemePageProps = {
+  themeId: string | null;
+  onBack: () => void;
+  onOpenDetail: (gameId: string) => void;
+  /** 直接进族谱页（树的全屏版本）；主题页内已内嵌渲染同一棵树。 */
+  onOpenLineage?: (rootGameId: string, fromGameId?: string) => void;
+  onOpenCompare?: (leftGameId: string, rightGameId: string) => void;
+};
+
+/** 成员根卡片：作品摘要 + 「查看作品 / 查看作品族谱」两个入口。 */
+function ThemeRootCard({
+  root,
+  onOpenDetail,
+  onOpenLineage,
+}: {
+  root: {
+    id: string;
+    title: string;
+    author: { id: string; name: string };
+    playCount: number;
+    lineage?: { generation: number } | null;
+  };
+  onOpenDetail: (gameId: string) => void;
+  onOpenLineage?: (rootGameId: string, fromGameId?: string) => void;
+}) {
+  const authorName = useGameAuthorDisplayName(root.author);
+  const generation = root.lineage?.generation ?? 0;
+  return (
+    <header className="game-theme-root__head">
+      <span className="game-theme-root__generation">
+        {generation === 0 ? '母版' : `第 ${generation} 代`}
+      </span>
+      <h3 className="game-theme-root__title">{root.title}</h3>
+      <p className="game-theme-root__meta">
+        <span>{authorName?.trim() || '未署名作者'}</span>
+        <span aria-hidden="true">·</span>
+        <span>{root.playCount.toLocaleString()} 次游玩</span>
+      </p>
+      <div className="game-theme-root__actions">
+        <PlatformActionButton
+          tone="secondary"
+          size="sm"
+          shape="pill"
+          onClick={() => onOpenDetail(root.id)}
+        >
+          查看作品
+        </PlatformActionButton>
+        {onOpenLineage ? (
+          <PlatformActionButton
+            tone="secondary"
+            size="sm"
+            shape="pill"
+            onClick={() => onOpenLineage(root.id, root.id)}
+          >
+            全屏查看族谱
+          </PlatformActionButton>
+        ) : null}
+      </div>
+    </header>
+  );
+}
+
+/**
+ * 主题页：标题 / 简介 / 角标 + 成员根清单，**逐根内嵌渲染作品树**。
+ *
+ * 树不在这里重建：内嵌的就是族谱页组件（`GameLineagePage embedded`），因此树查询、可见性过滤、
+ * 排序与截断全部复用 M3 那一份实现，主题页不引入第二套树规则。代价是每个根一次 `/lineage`
+ * 请求（技术方案 §3.10.4 已接受的 N+1 取舍）。
+ *
+ * 已发布但可见成员为空 → 明确空态（不是错误）；主题不存在 / 未发布 → 服务端 404，这里走错误态。
+ */
+export function GameThemePage({
+  themeId,
+  onBack,
+  onOpenDetail,
+  onOpenLineage,
+  onOpenCompare,
+}: GameThemePageProps) {
+  const normalizedThemeId = themeId?.trim() ?? '';
+  const [theme, setTheme] = useState<GameDistributionThemeDetail | null>(null);
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState('');
+
+  const loadTheme = useCallback(async () => {
+    if (!normalizedThemeId) {
+      setTheme(null);
+      setError('主题编号无效');
+      return;
+    }
+    setIsLoading(true);
+    setError('');
+    try {
+      const detail = await getTheme(normalizedThemeId);
+      if (!detail) {
+        setError('主题不存在或尚未发布');
+        return;
+      }
+      setTheme(detail);
+    } catch (loadError: unknown) {
+      setError(
+        loadError instanceof Error
+          ? loadError.message
+          : '主题不存在或尚未发布',
+      );
+    } finally {
+      setIsLoading(false);
+    }
+  }, [normalizedThemeId]);
+
+  useEffect(() => {
+    void loadTheme();
+  }, [loadTheme]);
+
+  return (
+    <div className="game-page game-theme-page">
+      <button type="button" className="game-back-button" onClick={onBack}>
+        <ArrowLeft /> 返回
+      </button>
+      <div className="game-toolbar">
+        <div className="game-toolbar__title">
+          <span className="game-eyebrow">共创主题</span>
+          <h2>{theme?.name?.trim() || '共创主题'}</h2>
+        </div>
+        <PlatformActionButton
+          tone="secondary"
+          size="sm"
+          shape="pill"
+          disabled={isLoading}
+          onClick={() => void loadTheme()}
+        >
+          <RefreshCcw aria-hidden="true" /> 刷新
+        </PlatformActionButton>
+      </div>
+
+      {theme?.badge || theme?.summary ? (
+        <div className="game-theme-summary">
+          {theme.badge ? (
+            <span className="game-theme-summary__badge">{theme.badge}</span>
+          ) : null}
+          {theme.summary ? (
+            <p className="game-theme-summary__text">{theme.summary}</p>
+          ) : null}
+        </div>
+      ) : null}
+
+      {isLoading && !theme ? (
+        <div className="game-loading-panel">正在加载共创主题…</div>
+      ) : null}
+      {!isLoading && error ? (
+        <PlatformStatusMessage tone="error" surface="platform">
+          <span>{error}</span>
+          {normalizedThemeId ? (
+            <button
+              type="button"
+              className="game-lineage-retry"
+              onClick={() => void loadTheme()}
+            >
+              重试
+            </button>
+          ) : null}
+        </PlatformStatusMessage>
+      ) : null}
+      {!isLoading && !error && theme && theme.roots.length === 0 ? (
+        <PlatformEmptyState surface="subpanel" size="panel">
+          <span>这个主题还没有可展示的作品树。</span>
+        </PlatformEmptyState>
+      ) : null}
+      {!error && theme && theme.roots.length > 0 ? (
+        <div className="game-theme-trees">
+          {theme.roots.map((root) => (
+            <section
+              key={root.id}
+              className="game-theme-root"
+              aria-label={`${root.title} 的作品树`}
+            >
+              <ThemeRootCard
+                root={root}
+                onOpenDetail={onOpenDetail}
+                onOpenLineage={onOpenLineage}
+              />
+              {/*
+                内嵌族谱页：树查询与渲染完全复用 M3 实现（embedded 只隐藏页面外壳：
+                返回按钮 / 页头 / 脚注），不在主题侧重建第二套树。
+              */}
+              <GameLineagePage
+                embedded
+                rootGameId={root.id}
+                highlightGameId={root.id}
+                onBack={onBack}
+                onOpenDetail={onOpenDetail}
+                onOpenCompare={onOpenCompare}
+              />
+            </section>
+          ))}
+        </div>
+      ) : null}
+
+      <p className="game-detail-footnote">
+        树只展示已公开的作品；成员作品下架或删除后会从主题里消失，重新公开后自动回来。
+      </p>
+    </div>
+  );
+}
+
+export default GameThemePage;

src/components/game-distribution/GameThemesPage.tsx

@@ -0,0 +1,168 @@
+import './gameDistribution.css';
+
+import { ArrowLeft, RefreshCcw } from 'lucide-react';
+import { useCallback, useEffect, useState } from 'react';
+
+import {
+  type GameDistributionThemeSummary,
+  listThemes,
+} from '../../services/gameDistributionClient';
+import { PlatformActionButton } from '../common/PlatformActionButton';
+import { PlatformEmptyState } from '../common/PlatformEmptyState';
+import { PlatformStatusMessage } from '../common/PlatformStatusMessage';
+
+type GameThemesPageProps = {
+  onBack: () => void;
+  /** 「游戏广场」页签：回到 `/games`（同一个 stage 的既有页面）。 */
+  onOpenGallery: () => void;
+  onOpenTheme: (themeId: string) => void;
+};
+
+/**
+ * 共创主题列表（游戏区的「共创」页签）。
+ *
+ * 匿名可读；分页沿用服务端游标惯例（默认 20 / 上限 50 / 末页 nextCursor 为 null）：
+ * 只有 `nextCursor` 非空才渲染「加载更多」，点击时把已加载的页追加在后面。
+ */
+export function GameThemesPage({
+  onBack,
+  onOpenGallery,
+  onOpenTheme,
+}: GameThemesPageProps) {
+  const [themes, setThemes] = useState<GameDistributionThemeSummary[]>([]);
+  const [nextCursor, setNextCursor] = useState<string | null>(null);
+  const [isLoading, setIsLoading] = useState(false);
+  const [error, setError] = useState('');
+
+  const loadThemes = useCallback(async (cursor?: string) => {
+    setIsLoading(true);
+    setError('');
+    try {
+      const page = await listThemes(cursor);
+      setThemes((current) =>
+        cursor ? [...current, ...page.themes] : page.themes,
+      );
+      setNextCursor(page.nextCursor);
+    } catch (loadError: unknown) {
+      setError(
+        loadError instanceof Error ? loadError.message : '读取共创主题失败',
+      );
+    } finally {
+      setIsLoading(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    void loadThemes();
+  }, [loadThemes]);
+
+  return (
+    <div className="game-page game-themes-page">
+      <button type="button" className="game-back-button" onClick={onBack}>
+        <ArrowLeft /> 返回
+      </button>
+      <div className="game-toolbar">
+        <div className="game-toolbar__title">
+          <span className="game-eyebrow">游戏</span>
+          <h2>共创主题</h2>
+        </div>
+        <PlatformActionButton
+          tone="secondary"
+          size="sm"
+          shape="pill"
+          disabled={isLoading}
+          onClick={() => void loadThemes()}
+        >
+          <RefreshCcw aria-hidden="true" /> 刷新
+        </PlatformActionButton>
+      </div>
+      <div className="game-category-tabs" role="tablist" aria-label="游戏区">
+        <button
+          type="button"
+          role="tab"
+          aria-selected={false}
+          className="game-category-tab"
+          onClick={onOpenGallery}
+        >
+          游戏
+        </button>
+        <button
+          type="button"
+          role="tab"
+          aria-selected
+          className="game-category-tab game-category-tab--active"
+        >
+          共创
+        </button>
+      </div>
+
+      {error ? (
+        <PlatformStatusMessage tone="error" surface="platform">
+          <span>{error}</span>
+          <button
+            type="button"
+            className="game-lineage-retry"
+            onClick={() => void loadThemes()}
+          >
+            重试
+          </button>
+        </PlatformStatusMessage>
+      ) : null}
+      {isLoading && themes.length === 0 ? (
+        <div className="game-loading-panel">正在加载共创主题…</div>
+      ) : null}
+      {!isLoading && !error && themes.length === 0 ? (
+        <PlatformEmptyState surface="subpanel" size="panel">
+          <span>还没有已发布的共创主题，稍后再来看看。</span>
+        </PlatformEmptyState>
+      ) : null}
+      {themes.length > 0 ? (
+        <>
+          <ul className="game-theme-list">
+            {themes.map((theme) => (
+              <li key={theme.themeId}>
+                <button
+                  type="button"
+                  className="game-theme-card"
+                  onClick={() => onOpenTheme(theme.themeId)}
+                >
+                  {theme.badge ? (
+                    <span className="game-theme-card__badge">{theme.badge}</span>
+                  ) : null}
+                  <span className="game-theme-card__name">{theme.name}</span>
+                  {theme.summary ? (
+                    <span className="game-theme-card__summary">
+                      {theme.summary}
+                    </span>
+                  ) : null}
+                  <span className="game-theme-card__meta">
+                    {theme.memberCount} 棵作品树
+                  </span>
+                </button>
+              </li>
+            ))}
+          </ul>
+          {nextCursor ? (
+            <div className="game-empty-actions">
+              <PlatformActionButton
+                tone="secondary"
+                size="sm"
+                shape="pill"
+                disabled={isLoading}
+                onClick={() => void loadThemes(nextCursor)}
+              >
+                加载更多
+              </PlatformActionButton>
+            </div>
+          ) : null}
+        </>
+      ) : null}
+
+      <p className="game-detail-footnote">
+        共创主题由平台命名，一个主题可以包含多棵作品树；作品之间仍各自独立展示。
+      </p>
+    </div>
+  );
+}
+
+export default GameThemesPage;

src/components/game-distribution/gameDistribution.css

@@ -567,6 +567,156 @@
   font-weight: 600;
   cursor: pointer;
 }
+/* 共创主题：列表卡片与主题页（成员根 + 内嵌作品树）。 */
+.game-theme-list {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(min(18rem, 100%), 1fr));
+  gap: 0.7rem;
+  margin: 0;
+  padding: 0;
+  list-style: none;
+}
+.game-theme-card {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  gap: 0.25rem;
+  width: 100%;
+  box-sizing: border-box;
+  border: 1px solid var(--platform-surface-border);
+  border-radius: 0.75rem;
+  padding: 0.8rem 0.9rem;
+  background: var(--platform-surface, #fff);
+  color: var(--platform-text-base);
+  font: inherit;
+  text-align: left;
+  cursor: pointer;
+}
+.game-theme-card:hover {
+  border-color: var(--platform-accent-strong);
+}
+.game-theme-card__badge {
+  border-radius: 999px;
+  padding: 0.1rem 0.5rem;
+  background: rgba(199, 101, 61, 0.14);
+  color: var(--platform-accent-strong);
+  font-size: 0.7rem;
+  font-weight: 700;
+}
+.game-theme-card__name {
+  color: var(--platform-text-strong);
+  font-size: 0.95rem;
+  font-weight: 700;
+  overflow-wrap: anywhere;
+}
+.game-theme-card__summary,
+.game-theme-card__meta {
+  color: var(--platform-text-soft);
+  font-size: 0.78rem;
+  overflow-wrap: anywhere;
+}
+.game-theme-summary {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.4rem;
+}
+.game-theme-summary__badge {
+  border-radius: 999px;
+  padding: 0.12rem 0.6rem;
+  background: rgba(199, 101, 61, 0.14);
+  color: var(--platform-accent-strong);
+  font-size: 0.74rem;
+  font-weight: 700;
+}
+.game-theme-summary__text {
+  margin: 0;
+  color: var(--platform-text-soft);
+  font-size: 0.8rem;
+  line-height: 1.6;
+  overflow-wrap: anywhere;
+}
+.game-theme-trees {
+  display: flex;
+  flex-direction: column;
+  gap: 1.1rem;
+}
+.game-theme-root {
+  display: flex;
+  flex-direction: column;
+  gap: 0.55rem;
+  min-width: 0;
+  border: 1px solid var(--platform-surface-border);
+  border-radius: 0.85rem;
+  padding: 0.8rem 0.9rem;
+}
+.game-theme-root__head {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.4rem;
+}
+.game-theme-root__generation {
+  border-radius: 999px;
+  padding: 0.1rem 0.5rem;
+  background: var(--platform-surface-border);
+  color: var(--platform-text-soft);
+  font-size: 0.7rem;
+  font-weight: 700;
+}
+.game-theme-root__title {
+  margin: 0;
+  color: var(--platform-text-strong);
+  font-size: 0.95rem;
+  overflow-wrap: anywhere;
+}
+.game-theme-root__meta {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.3rem;
+  margin: 0;
+  color: var(--platform-text-soft);
+  font-size: 0.78rem;
+  overflow-wrap: anywhere;
+}
+.game-theme-root__actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.35rem;
+}
+/* 内嵌的族谱页：去掉页面级留白，避免主题页里出现两层「页面」盒。 */
+.game-lineage-page--embedded {
+  max-width: none;
+  margin: 0;
+}
+.game-detail-info-card .game-fork-theme-list {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.3rem;
+  justify-items: start;
+}
+.game-detail-info-card .game-fork-theme-link {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.25rem;
+  border: 1px solid var(--platform-surface-border);
+  border-radius: 999px;
+  padding: 0.18rem 0.6rem;
+  background: transparent;
+  color: var(--platform-text-base);
+  font: inherit;
+  font-size: 0.74rem;
+  font-weight: 600;
+  cursor: pointer;
+  overflow-wrap: anywhere;
+}
+.game-detail-info-card .game-fork-theme-link:hover {
+  color: var(--platform-text-strong);
+}
+.game-detail-info-card .game-fork-theme-badge {
+  color: var(--platform-accent-strong);
+  font-weight: 700;
+}
 .game-loading-panel {
   display: grid;
   min-height: 18rem;

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

@@ -55,6 +55,8 @@ const gameDistributionMock = vi.hoisted(() => ({
   getDerivedGames: vi.fn(),
   getGame: vi.fn(),
   getGameLineage: vi.fn(),
+  getTheme: vi.fn(),
+  listThemes: vi.fn(),
   getGameVersion: vi.fn(),
   getMyGame: vi.fn(),
   listGames: vi.fn(),
@@ -1494,3 +1496,106 @@ describe('创作族谱', () => {
     );
   });
 });
+
+describe('共创主题', () => {
+  it('广场「共创」页签切到主题列表', async () => {
+    window.history.replaceState(null, '', '/games');
+    gameDistributionMock.listGames.mockResolvedValue([]);
+    gameDistributionMock.listThemes.mockResolvedValue({
+      themes: [],
+      nextCursor: null,
+    });
+    const setSelectionStage = vi.fn();
+
+    render(
+      <PlatformEntryFlowShellImpl
+        selectionStage="games"
+        setSelectionStage={setSelectionStage}
+      />,
+    );
+
+    fireEvent.click(await screen.findByRole('tab', { name: '共创' }));
+    expect(setSelectionStage).toHaveBeenCalledWith('game-themes', {
+      path: '/games/themes',
+    });
+  });
+
+  it('主题列表页渲染主题并进入主题页', async () => {
+    window.history.replaceState(null, '', '/games/themes');
+    gameDistributionMock.listThemes.mockResolvedValue({
+      themes: [
+        {
+          themeId: 'theme-1',
+          name: '精选共创',
+          summary: '运营精选',
+          badge: '精选',
+          memberCount: 1,
+        },
+      ],
+      nextCursor: null,
+    });
+    const setSelectionStage = vi.fn();
+
+    render(
+      <PlatformEntryFlowShellImpl
+        selectionStage="game-themes"
+        setSelectionStage={setSelectionStage}
+      />,
+    );
+
+    fireEvent.click(await screen.findByRole('button', { name: /精选共创/u }));
+    expect(setSelectionStage).toHaveBeenCalledWith('game-theme', {
+      path: '/games/theme?id=theme-1',
+    });
+  });
+
+  it('主题详情按 ?id= 渲染主题名与成员根，并复用族谱查询', async () => {
+    window.history.replaceState(null, '', '/games/theme?id=theme-1');
+    gameDistributionMock.getTheme.mockResolvedValue({
+      themeId: 'theme-1',
+      name: '精选共创',
+      summary: '运营精选',
+      badge: '精选',
+      memberCount: 1,
+      roots: [
+        {
+          id: 'game-root-1',
+          title: '根作品',
+          summary: '根',
+          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: null,
+          playCount: 1,
+          createdAt: '2026-09-18T00:00:00.000Z',
+        },
+      ],
+    });
+    gameDistributionMock.getGameLineage.mockResolvedValue({
+      rootGameId: 'game-root-1',
+      root: null,
+      nodes: [],
+      truncated: false,
+    });
+
+    render(
+      <PlatformEntryFlowShellImpl
+        selectionStage="game-theme"
+        setSelectionStage={vi.fn()}
+      />,
+    );
+
+    expect(await screen.findByRole('heading', { name: '精选共创' })).toBeTruthy();
+    expect(screen.getByText('根作品')).toBeTruthy();
+    expect(gameDistributionMock.getTheme).toHaveBeenCalledWith('theme-1');
+    // 树复用既有族谱查询：按根请求一次。
+    expect(gameDistributionMock.getGameLineage).toHaveBeenCalledWith(
+      'game-root-1',
+    );
+  });
+});

src/components/platform-entry/PlatformEntryActiveFlowShell.tsx

@@ -125,6 +125,16 @@ const GameComparePage = lazy(async () => {
   return { default: module.GameComparePage };
 });
 
+const GameThemesPage = lazy(async () => {
+  const module = await import('../game-distribution/GameThemesPage');
+  return { default: module.GameThemesPage };
+});
+
+const GameThemePage = lazy(async () => {
+  const module = await import('../game-distribution/GameThemePage');
+  return { default: module.GameThemePage };
+});
+
 type ActiveRailButtonProps = {
   active: boolean;
   emphasized?: boolean;
@@ -593,6 +603,38 @@ export function PlatformEntryFlowShellImpl({
     setSelectionStage('games', { path: '/games' });
   }, [setSelectionStage]);
 
+  /** 共创主题列表（`/games` 的「共创」页签）。 */
+  const openGameThemes = useCallback(() => {
+    setSelectionStage('game-themes', { path: '/games/themes' });
+  }, [setSelectionStage]);
+
+  const backFromGameThemes = useCallback(() => {
+    if (hasAppHistoryBackEntry()) {
+      window.history.back();
+      return;
+    }
+    replaceAppHistoryPath('/games');
+    setSelectionStage('games', { path: '/games' });
+  }, [setSelectionStage]);
+
+  /** 主题详情：复用 `?id=` 约定（与 `/games/lineage?id=`、`/games/detail?id=` 同款）。 */
+  const openGameTheme = useCallback(
+    (themeId: string) => {
+      const path = `/games/theme?id=${encodeURIComponent(themeId)}`;
+      setSelectionStage('game-theme', { path });
+    },
+    [setSelectionStage],
+  );
+
+  const backFromGameTheme = useCallback(() => {
+    if (hasAppHistoryBackEntry()) {
+      window.history.back();
+      return;
+    }
+    replaceAppHistoryPath('/games/themes');
+    setSelectionStage('game-themes', { path: '/games/themes' });
+  }, [setSelectionStage]);
+
   /**
    * 详情页可能从广场或「我的游戏」进入，返回优先走浏览器原生返回，这样能回到
    * 用户真正的来源页；直接打开详情链接等没有可回退的应用内历史时再兜底回广场。
@@ -728,6 +770,8 @@ export function PlatformEntryFlowShellImpl({
     selectionStage === 'games' ||
     selectionStage === 'game-detail' ||
     selectionStage === 'game-compare' ||
+    selectionStage === 'game-themes' ||
+    selectionStage === 'game-theme' ||
     selectionStage === 'game-play' ||
     selectionStage === 'game-mine' ||
     selectionStage === 'game-lineage' ||
@@ -1002,6 +1046,7 @@ export function PlatformEntryFlowShellImpl({
                         searchKeyword={activeSearchKeyword}
                         onOpenDetail={openGameDetail}
                         onOpenMyGames={openMyGames}
+                        onOpenThemes={openGameThemes}
                         onOpenPublish={
                           gamePublishGateAllowed ? openGamePublish : undefined
                         }
@@ -1037,6 +1082,7 @@ export function PlatformEntryFlowShellImpl({
                         onPlay={openGamePlay}
                         onOpenLineage={openGameLineage}
                         onOpenCompare={openGameCompare}
+                        onOpenTheme={openGameTheme}
                       />
                     ) : selectionStage === 'game-lineage' ? (
                       <GameLineagePage
@@ -1053,6 +1099,20 @@ export function PlatformEntryFlowShellImpl({
                         onBack={backFromGameCompare}
                         onOpenDetail={openGameDetail}
                       />
+                    ) : selectionStage === 'game-themes' ? (
+                      <GameThemesPage
+                        onBack={backFromGameThemes}
+                        onOpenGallery={openGames}
+                        onOpenTheme={openGameTheme}
+                      />
+                    ) : selectionStage === 'game-theme' ? (
+                      <GameThemePage
+                        themeId={gameId}
+                        onBack={backFromGameTheme}
+                        onOpenDetail={openGameDetail}
+                        onOpenLineage={openGameLineage}
+                        onOpenCompare={openGameCompare}
+                      />
                     ) : (
                       <GamePlayPage gameId={gameId} onBack={backFromGamePlay} />
                     )}

src/components/platform-entry/platformEntryActiveTypes.ts

@@ -11,6 +11,8 @@ export type SelectionStage =
   | 'games'
   | 'game-detail'
   | 'game-compare'
+  | 'game-themes'
+  | 'game-theme'
   | 'game-play'
   | 'game-mine'
   | 'game-lineage'

src/routing/activeAppPageRoutes.test.ts

@@ -29,6 +29,8 @@ describe('appPageRoutes', () => {
     expect(resolveSelectionStageFromPath('/games/compare')).toBe(
       'game-compare',
     );
+    expect(resolveSelectionStageFromPath('/games/themes')).toBe('game-themes');
+    expect(resolveSelectionStageFromPath('/games/theme')).toBe('game-theme');
     expect(resolveSelectionStageFromPath('/games/play')).toBe('game-play');
     expect(resolveSelectionStageFromPath('/games/mine')).toBe('game-mine');
     expect(resolveSelectionStageFromPath('/games/lineage')).toBe(
@@ -51,6 +53,8 @@ describe('appPageRoutes', () => {
     expect(resolvePathForSelectionStage('profile')).toBe('/profile');
     expect(resolvePathForSelectionStage('games')).toBe('/games');
     expect(resolvePathForSelectionStage('game-compare')).toBe('/games/compare');
+    expect(resolvePathForSelectionStage('game-themes')).toBe('/games/themes');
+    expect(resolvePathForSelectionStage('game-theme')).toBe('/games/theme');
     expect(resolvePathForSelectionStage('game-mine')).toBe('/games/mine');
     expect(resolvePathForSelectionStage('game-lineage')).toBe(
       '/games/lineage',

src/routing/activeAppPageRoutes.ts

@@ -16,6 +16,8 @@ const STAGE_ROUTE_ENTRIES = [
   ['games', '/games'],
   ['game-detail', '/games/detail'],
   ['game-compare', '/games/compare'],
+  ['game-themes', '/games/themes'],
+  ['game-theme', '/games/theme'],
   ['game-play', '/games/play'],
   ['game-mine', '/games/mine'],
   ['game-lineage', '/games/lineage'],

src/services/activeAppTitle.test.ts

@@ -42,6 +42,12 @@ describe('activeAppTitle', () => {
     expect(resolveAppTitleForSelectionStage('game-compare')).toBe(
       '原版与二创对比 - 陶泥儿',
     );
+    expect(resolveAppTitleForSelectionStage('game-themes')).toBe(
+      '共创主题 - 陶泥儿',
+    );
+    expect(resolveAppTitleForSelectionStage('game-theme')).toBe(
+      '共创主题详情 - 陶泥儿',
+    );
     expect(resolveAppTitleForSelectionStage('game-publish')).toBe(
       '发布游戏 - 陶泥儿',
     );

src/services/activeAppTitle.ts

@@ -17,6 +17,8 @@ const APP_TITLE_BY_SELECTION_STAGE: Record<SelectionStage, string> = {
   games: '游戏 - 陶泥儿',
   'game-detail': '游戏详情 - 陶泥儿',
   'game-compare': '原版与二创对比 - 陶泥儿',
+  'game-themes': '共创主题 - 陶泥儿',
+  'game-theme': '共创主题详情 - 陶泥儿',
   'game-play': '正在游玩 - 陶泥儿',
   'game-mine': '我的游戏 - 陶泥儿',
   'game-lineage': '创作族谱 - 陶泥儿',

src/services/gameDistributionClient.ts

@@ -373,8 +373,114 @@ export async function getGame(gameId: string) {
  */
 export type GameDistributionGameWithCollection = GameDistributionGame & {
   collected?: boolean;
+  /**
+   * 该作品所属的公开共创主题（先取作品的根再按根反查，因此**第 N 代作品也会有值**）。
+   * 匿名也返回：没有所属主题时是 `[]` 而不是缺键。
+   */
+  themes?: GameDistributionThemeReference[];
 };
 
+/** 作品详情里的主题入口：只够渲染一个跳转（简介与成员数在主题页取）。 */
+export type GameDistributionThemeReference = {
+  themeId: string;
+  name: string;
+  badge: string;
+};
+
+/** 共创主题摘要（公开列表条目）。 */
+export type GameDistributionThemeSummary = {
+  themeId: string;
+  name: string;
+  summary: string;
+  badge: string;
+  /** 当前**可见**成员数（与主题详情 `roots` 长度同口径，不含草稿/已下架成员）。 */
+  memberCount: number;
+};
+
+/** 主题详情：摘要 + 成员根清单（逐条是公开目录同一份投影）。 */
+export type GameDistributionThemeDetail = GameDistributionThemeSummary & {
+  roots: GameDistributionGame[];
+};
+
+function normalizeThemeList(value: unknown): GameDistributionThemeSummary[] {
+  if (!Array.isArray(value)) return [];
+  return value.flatMap((item) => {
+    if (!item || typeof item !== 'object') return [];
+    const theme = item as Partial<GameDistributionThemeSummary>;
+    const themeId = typeof theme.themeId === 'string' ? theme.themeId.trim() : '';
+    const name = typeof theme.name === 'string' ? theme.name.trim() : '';
+    if (!themeId || !name) return [];
+    return [
+      {
+        themeId,
+        name,
+        summary: typeof theme.summary === 'string' ? theme.summary : '',
+        badge: typeof theme.badge === 'string' ? theme.badge : '',
+        memberCount:
+          typeof theme.memberCount === 'number' && theme.memberCount >= 0
+            ? theme.memberCount
+            : 0,
+      },
+    ];
+  });
+}
+
+/**
+ * 共创主题列表（匿名可读）。分页与 `/my-collections` 同口径：服务端默认 20 / 上限 50，
+ * `nextCursor` 是真实游标（末页为 `null`），客户端只在非空时渲染「加载更多」。
+ */
+export async function listThemes(cursor?: string) {
+  const params = new URLSearchParams();
+  const normalizedCursor = cursor?.trim();
+  if (normalizedCursor) params.set('cursor', normalizedCursor);
+  const query = params.toString();
+  const payload = await requestJson<{
+    themes?: unknown;
+    nextCursor?: string | null;
+  }>(
+    `/themes${query ? `?${query}` : ''}`,
+    { method: 'GET', cache: 'no-store' },
+    '读取共创主题失败',
+    PUBLIC_GAME_REQUEST_OPTIONS,
+  );
+  return {
+    themes: normalizeThemeList(payload.themes),
+    nextCursor: payload.nextCursor ?? null,
+  };
+}
+
+/**
+ * 共创主题详情（匿名可读）。主题不存在 / 未发布一律 404（服务端不返回空壳），
+ * 这里按失败抛出，由主题页渲染成「主题不存在或尚未发布」的降级态。
+ */
+export async function getTheme(
+  themeId: string,
+): Promise<GameDistributionThemeDetail | null> {
+  const normalizedThemeId = themeId.trim();
+  if (!normalizedThemeId) return null;
+  const payload = await requestJson<{
+    themeId?: string;
+    name?: string;
+    summary?: string;
+    badge?: string;
+    memberCount?: number;
+    roots?: unknown;
+  }>(
+    `/themes/${encodeURIComponent(normalizedThemeId)}`,
+    { method: 'GET', cache: 'no-store' },
+    '读取共创主题失败',
+    PUBLIC_GAME_REQUEST_OPTIONS,
+  );
+  return {
+    themeId: payload.themeId ?? normalizedThemeId,
+    name: payload.name ?? '',
+    summary: payload.summary ?? '',
+    badge: payload.badge ?? '',
+    memberCount: payload.memberCount ?? 0,
+    roots: normalizeGameList(payload.roots),
+  };
+}
+
 /** 收藏切换的响应；DELETE 不带 `replayed`。 */
 export type GameDistributionCollectionState = {
   collected: boolean;