docs(i18n): 恢复并补齐英文版 vitepress，README 默认改为英文

- README 默认英文：README.en.md → README.md（英文为默认），中文移至 README.zh-CN.md，语言切换链接同步
- 恢复被删除的 docs/en/ 英文文档（git 历史 cc5e53c5^），删除 4 篇已废弃文件
- 英文导航 config.ts 对齐中文结构（新增 Deployment/Changelog 侧栏，同步 Guide/Design 条目）
- 翻译 15 篇中文新增文档：guide 5 篇（certificates/pages-usage/proxy-config/uptime-kuma/zone-domain-migration）+ design 10 篇（zone-design/cloudflare-pointing/waf-orchestration/origin-error-page/edge-cache-design/pages-design/logstore/kuma-design/login-captcha/observability 三篇）
- en 首页更新（新增 Pages 特性、tagline 同步）；changelog 英文入口指向中文版
- vitepress 构建验证：43 个英文页面全部渲染

注意：29 篇旧英文文档为恢复版，部分内容（如 deployment/server、reference/configuration）可能落后于中文，需后续逐篇同步

frontend/components/common/home/home-main.tsx

@@ -35,7 +35,7 @@ export function HomeMain() {
       title: '使用文档',
       description: '学习如何集成 API 及日常操作帮助指南',
       icon: HelpCircle,
-      url: 'https://open-flare.pages.dev/',
+      url: 'https://openflare.fyrn.link/',
       color: 'text-purple-500',
       bgColor: 'bg-purple-500/10',
       borderColor: 'hover:border-purple-500/30',

frontend/components/common/settings/other-tab.tsx

@@ -193,7 +193,7 @@ const MENU_GROUPS: MenuGroup[] = [
     nameKey: 'groupDocs',
     items: [
       {
-        path: 'https://open-flare.pages.dev/',
+        path: 'https://openflare.fyrn.link/',
         labelKey: 'usageDocs',
         descKey: 'descUsageDocs',
         icon: FileText,

frontend/components/home/developer-section.tsx

@@ -161,7 +161,7 @@ curl -X POST https://api.example.com/api/v1/auth/register \\
 
             <div className='flex flex-wrap gap-4'>
               <Link
-                href='https://open-flare.pages.dev/'
+                href='https://openflare.fyrn.link/'
                 target='_blank'
                 rel='noopener noreferrer'
               >

frontend/components/home/footer-section.tsx

@@ -75,7 +75,7 @@ export const FooterSection = React.memo(function FooterSection({
             <h3 className='font-semibold text-foreground mb-6'>开发</h3>
             <ul className='space-y-4 text-sm text-muted-foreground'>
               <li>
-                <FooterLink href='https://open-flare.pages.dev/'>
+                <FooterLink href='https://openflare.fyrn.link/'>
                   使用文档
                 </FooterLink>
               </li>

frontend/components/home/hero-section.tsx

@@ -83,7 +83,7 @@ export const HeroSection = React.memo(function HeroSection({
               </Link>
 
               <Link
-                href='https://open-flare.pages.dev/'
+                href='https://openflare.fyrn.link/'
                 target='_blank'
                 rel='noopener noreferrer'
                 className='w-full sm:w-auto'

frontend/components/layout/header.tsx

@@ -255,7 +255,7 @@ function AppBanner() {
             <p className='flex flex-wrap items-center justify-center gap-x-2 text-center'>
               <span className='text-foreground'>{t('bannerTitle')}</span>
               <a
-                href='https://open-flare.pages.dev/changelog/'
+                href='https://openflare.fyrn.link/changelog/'
                 target='_blank'
                 className='underline underline-offset-4 hover:text-foreground'
               >

frontend/components/layout/sidebar.tsx

@@ -85,7 +85,7 @@ const adminItems: NavItem[] = [
 const documentItems: NavItem[] = [
   {
     titleKey: 'usageDocs',
-    url: 'https://open-flare.pages.dev/',
+    url: 'https://openflare.fyrn.link/',
     icon: FileText,
     external: true,
   },
@@ -332,7 +332,7 @@ export function AppSidebar({ ...props }: React.ComponentProps<typeof Sidebar>) {
               <DropdownMenuItem
                 onClick={() => {
                   window.open(
-                    'https://open-flare.pages.dev/',
+                    'https://openflare.fyrn.link/',
                     '_blank',
                     'noopener,noreferrer',
                   );

frontend/lib/utils/search-data.ts

@@ -65,7 +65,7 @@ export const searchData: SearchItemSource[] = [
     id: 'docs-how-to-use',
     titleKey: 'nav.usageDocs',
     descriptionKey: 'search.items.usageDocsDesc',
-    url: 'https://open-flare.pages.dev/',
+    url: 'https://openflare.fyrn.link/',
     category: 'page',
     keywords: ['docs', '文档', '使用', 'how to', 'tutorial', '教程', 'help'],
   },