发布入口接入灰度开关

- 后端：GET /api/runtime/frontend-config 新增 gameDistributionPublishEnabled，复用 `game-distribution:publish` 判据（未配置或 enabled=false 时对已登录作者默认开放，显式收紧后只放行白名单/灰度命中用户，匿名恒为 false），前端入口与写入口共用同一事实源。
- 后端用例：新增 frontend_runtime_config_game_distribution_publish_is_scoped_to_authenticated_gate，覆盖默认开放、enabled=true 无白名单、白名单命中、deny 名单、enabled=false 回退与 rolloutPercent=100。
- 网页：平台壳按灰度隐藏「发布游戏 / 发布新版本」入口；/games/publish 直接访问时渲染「发布功能正在灰度中」并提供重新检查；读取失败按放行处理，由后端写入口把关并返回可读文案。
- AGC：新增 readGamePublishAvailability（同一运行时配置字段），只有命中才把发布回调交给 DirectProject 聊天头；字段缺失或读取失败按不开放处理。
- 文档：玩法链路、后端数据契约与实施计划记录灰度口径、入口行为与验证命令。

src/components/platform-entry/PlatformEntryActiveFlowShell.tsx

@@ -25,6 +25,7 @@ import {
   pushAppHistoryPath,
   replaceAppHistoryPath,
 } from '../../routing/activeAppPageRoutes';
+import { loadFrontendRuntimeConfig } from '../../services/frontendRuntimeConfigService';
 import { getPlatformProfileDashboard } from '../../services/platform-entry/platformProfileClient';
 import { usePlatformWalletStore } from '../../stores/usePlatformWalletStore';
 import { useAuthUi } from '../auth/AuthUiContext';
@@ -280,6 +281,9 @@ export function PlatformEntryFlowShellImpl({
   setSelectionStage,
 }: PlatformEntryFlowShellProps) {
   const authUi = useAuthUi();
+  // 发布灰度：命中才暴露「发布游戏 / 发布新版本」入口；读取失败按放行处理，由后端写入口把关。
+  const [gamePublishGateAllowed, setGamePublishGateAllowed] = useState(true);
+  const gamePublishGateUserId = authUi?.user?.id ?? '';
   const [dashboard, setDashboard] = useState<ProfileDashboardSummary | null>(
     null,
   );
@@ -398,6 +402,29 @@ export function PlatformEntryFlowShellImpl({
     setSelectionStage('games', { path: '/games' });
   }, [setSelectionStage]);
 
+  useEffect(() => {
+    if (!gamePublishGateUserId) {
+      // 未登录时不展示发布入口，登录后由 authUi 变化触发重新读取。
+      setGamePublishGateAllowed(false);
+      return;
+    }
+    let cancelled = false;
+    loadFrontendRuntimeConfig()
+      .then((config) => {
+        if (!cancelled) {
+          setGamePublishGateAllowed(
+            config.gameDistributionPublishEnabled !== false,
+          );
+        }
+      })
+      .catch(() => {
+        if (!cancelled) setGamePublishGateAllowed(true);
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [gamePublishGateUserId]);
+
   const openGamePublish = useCallback(() => {
     setSelectionStage('game-publish', { path: '/games/publish' });
   }, [setSelectionStage]);
@@ -731,7 +758,9 @@ export function PlatformEntryFlowShellImpl({
                         searchKeyword={activeSearchKeyword}
                         onOpenDetail={openGameDetail}
                         onOpenMyGames={openMyGames}
-                        onOpenPublish={openGamePublish}
+                        onOpenPublish={
+                          gamePublishGateAllowed ? openGamePublish : undefined
+                        }
                       />
                     ) : selectionStage === 'game-publish' ? (
                       <GamePublishPage
@@ -743,7 +772,11 @@ export function PlatformEntryFlowShellImpl({
                       <MyGamesPage
                         onBack={openGames}
                         onOpenDetail={openGameDetail}
-                        onPublishVersion={openGamePublishVersion}
+                        onPublishVersion={
+                          gamePublishGateAllowed
+                            ? openGamePublishVersion
+                            : undefined
+                        }
                       />
                     ) : selectionStage === 'game-detail' ? (
                       <GameDetailPage