refactor: 企业级目录重构与播放/关于页体验升级

- 按 app / shared / entities / features 分层，路由懒加载并抽出布局组件
- 请求层改为可插拔拦截器，统一错误类型、超时取消与端点拆分
- 抽取播放器、骨架屏、网格等复用组件，点赞收藏接入统一交互反馈
- 关于页重做为无边框极光风格，补充 iOS / Google Play 下载入口
- 修复播放页滚轮切集吞事件、页面误滚动、后台持续播放与声音记忆问题
- 语言按本地偏好与 IP 识别，国旗改为内联 SVG
- 清理未使用的旧站点文件，补充 ESLint 配置

src/app/providers/AppProviders.jsx

@@ -0,0 +1,90 @@
+// Author: fruit.com.cn
+import { createContext, useCallback, useContext, useEffect, useMemo, useRef, useState } from 'react';
+import { getLocale } from '../../i18n';
+import { detectLocaleFromIp } from '../../shared/lib/geo';
+import { applySeo } from '../../shared/lib/seo';
+
+const LocaleContext = createContext(null);
+const UiContext = createContext(null);
+const LANG_STORAGE_KEY = 'ymb.lang';
+const SUPPORTED_LANGS = ['id', 'en', 'zh'];
+
+function readUrlLang() {
+  const value = new URLSearchParams(window.location.search).get('lang');
+  return SUPPORTED_LANGS.includes(value) ? value : '';
+}
+
+function readStoredLang() {
+  try {
+    const value = window.localStorage.getItem(LANG_STORAGE_KEY);
+    return SUPPORTED_LANGS.includes(value) ? value : '';
+  } catch {
+    return '';
+  }
+}
+
+function readNavigatorLang() {
+  const code = (navigator.language || '').toLowerCase();
+  if (code.startsWith('id')) return 'id';
+  if (code.startsWith('zh')) return 'zh';
+  return 'en';
+}
+
+function detectInitialLang() {
+  return readUrlLang() || readStoredLang() || readNavigatorLang();
+}
+
+export function AppProviders({ children }) {
+  const [lang, setLangState] = useState(detectInitialLang);
+  const [query, setQuery] = useState('');
+  const [sidebarOpen, setSidebarOpen] = useState(() => window.innerWidth > 760);
+  const userSelectedRef = useRef(false);
+  const locale = getLocale(lang);
+
+  // 首次进入且没有明确偏好时，按 IP 归属地自动匹配语言
+  useEffect(() => {
+    if (readUrlLang() || readStoredLang()) return undefined;
+    let active = true;
+    detectLocaleFromIp().then((detected) => {
+      if (active && detected && !userSelectedRef.current) setLangState(detected);
+    });
+    return () => {
+      active = false;
+    };
+  }, []);
+
+  const setLang = useCallback((next) => {
+    userSelectedRef.current = true;
+    setLangState(next);
+    try {
+      window.localStorage.setItem(LANG_STORAGE_KEY, next);
+    } catch {
+      // 隐私模式下写入失败时仍保证本次会话生效
+    }
+  }, []);
+
+  useEffect(() => {
+    applySeo(locale, window.location.pathname);
+  }, [lang, locale]);
+
+  const localeValue = useMemo(() => ({ lang, locale, setLang }), [lang, locale, setLang]);
+  const uiValue = useMemo(() => ({ query, setQuery, sidebarOpen, setSidebarOpen }), [query, sidebarOpen]);
+
+  return (
+    <LocaleContext.Provider value={localeValue}>
+      <UiContext.Provider value={uiValue}>{children}</UiContext.Provider>
+    </LocaleContext.Provider>
+  );
+}
+
+export function useLocale() {
+  const value = useContext(LocaleContext);
+  if (!value) throw new Error('useLocale must be used within AppProviders');
+  return value;
+}
+
+export function useUi() {
+  const value = useContext(UiContext);
+  if (!value) throw new Error('useUi must be used within AppProviders');
+  return value;
+}