feat(landing): extract i18n keys + add English translations

Replaces all rendered Chinese strings in LandingView with $t() calls and
<i18n-t> interpolation components; adds landing namespace (62 leaf keys) to
both zh.ts and en.ts.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/views/landing/LandingView.vue

@@ -13,13 +13,13 @@
           <span>PURO AI</span>
         </router-link>
         <div class="nav-links">
-          <a href="#features">产品</a>
-          <a href="/docs">文档</a>
+          <a href="#features">{{ $t('landing.nav.products') }}</a>
+          <a href="/docs">{{ $t('landing.nav.docs') }}</a>
         </div>
         <div class="nav-cta">
           <PuroLocaleSwitcher />
-          <router-link to="/login" class="btn btn-ghost">登录</router-link>
-          <router-link to="/register" class="btn btn-primary">免费试用 →</router-link>
+          <router-link to="/login" class="btn btn-ghost">{{ $t('landing.nav.login') }}</router-link>
+          <router-link to="/register" class="btn btn-primary">{{ $t('landing.nav.signup') }}</router-link>
         </div>
       </div>
     </nav>
@@ -27,32 +27,35 @@
     <!-- HERO -->
     <section class="hero container">
       <div class="hero-eyebrow">
-        <span class="badge">NEW</span>
-        <span>统一接入多个 AI 平台 · 零改动切换</span>
+        <span class="badge">{{ $t('landing.hero.badgeNew') }}</span>
+        <span>{{ $t('landing.hero.eyebrow') }}</span>
       </div>
       <h1 class="hero-title">
-        你的 AI 订阅，<br>
-        <span class="text-puro-cyan">已经付过钱了。</span>
+        {{ $t('landing.hero.title1') }}<br>
+        <span class="text-puro-cyan">{{ $t('landing.hero.title2') }}</span>
       </h1>
       <p class="hero-sub">
-        Claude Pro · ChatGPT Plus · Codex · Gemini 订阅<br>
-        聚合成统一 API，零改动接入 <span class="pill-inline">OpenAI</span> / <span class="pill-inline">Anthropic</span> SDK
+        {{ $t('landing.hero.sub1') }}<br>
+        <i18n-t keypath="landing.hero.sub2" tag="span">
+          <template #openai><span class="pill-inline">OpenAI</span></template>
+          <template #anthropic><span class="pill-inline">Anthropic</span></template>
+        </i18n-t>
       </p>
       <div class="hero-cta">
-        <router-link to="/login" class="btn btn-primary btn-lg">登录 →</router-link>
-        <a href="mailto:admin@puro.im" class="btn btn-ghost btn-lg">联系咨询</a>
+        <router-link to="/login" class="btn btn-primary btn-lg">{{ $t('landing.hero.ctaLogin') }}</router-link>
+        <a href="mailto:admin@puro.im" class="btn btn-ghost btn-lg">{{ $t('landing.hero.ctaContact') }}</a>
       </div>
       <div class="hero-micro">
-        已验证可用 Codex CLI · Claude Code · curl · 服务器出口新加坡
+        {{ $t('landing.hero.micro') }}
       </div>
     </section>
 
     <!-- ② 模型墙 -->
     <section class="block container" id="models">
       <div class="section-header">
-        <div class="section-kicker">// providers</div>
-        <h2 class="section-title">通过 OAuth 直接复用你的订阅</h2>
-        <p class="section-sub">无需申请官方 API key，也无需切换账号</p>
+        <div class="section-kicker">{{ $t('landing.models.kicker') }}</div>
+        <h2 class="section-title">{{ $t('landing.models.title') }}</h2>
+        <p class="section-sub">{{ $t('landing.models.sub') }}</p>
       </div>
       <div class="model-wall">
         <div class="model-card">
@@ -100,8 +103,8 @@
             <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="#94a3b8" stroke-width="1.6" stroke-linecap="round"><circle cx="5" cy="12" r="1.5" fill="#94a3b8"/><circle cx="12" cy="12" r="1.5" fill="#94a3b8"/><circle cx="19" cy="12" r="1.5" fill="#94a3b8"/></svg>
           </div>
           <div>
-            <div class="model-name">更多</div>
-            <div class="model-meta">规划中</div>
+            <div class="model-name">{{ $t('landing.models.more') }}</div>
+            <div class="model-meta">{{ $t('landing.models.morePlanned') }}</div>
           </div>
         </div>
       </div>
@@ -110,39 +113,43 @@
     <!-- ③ 三特性 -->
     <section class="block container" id="features">
       <div class="section-header">
-        <div class="section-kicker">// capabilities</div>
-        <h2 class="section-title">付一次订阅，<br>用起一整个模型池</h2>
-        <p class="section-sub">把散落在各个平台的订阅，整合成开发者真正能用的基础设施</p>
+        <div class="section-kicker">{{ $t('landing.features.kicker') }}</div>
+        <h2 class="section-title">{{ $t('landing.features.title1') }}<br>{{ $t('landing.features.title2') }}</h2>
+        <p class="section-sub">{{ $t('landing.features.sub') }}</p>
       </div>
       <div class="features">
         <div class="feature">
           <div class="feature-icon">⚡</div>
-          <h3>一个 key 接所有模型</h3>
-          <p>不再为每个 provider 申请 API key、配置 base_url。统一 <code class="mono">sk-</code> 走 Claude / GPT / Gemini，按 model 自动路由到对应账号池。</p>
+          <h3>{{ $t('landing.features.f1Title') }}</h3>
+          <p>
+            <i18n-t keypath="landing.features.f1Desc" tag="span">
+              <template #sk><code class="mono">sk-</code></template>
+            </i18n-t>
+          </p>
           <ul class="feature-bullets">
-            <li>OpenAI Responses API 兼容</li>
-            <li>Anthropic Messages API 兼容</li>
-            <li>智能 model → provider 路由</li>
+            <li>{{ $t('landing.features.f1b1') }}</li>
+            <li>{{ $t('landing.features.f1b2') }}</li>
+            <li>{{ $t('landing.features.f1b3') }}</li>
           </ul>
         </div>
         <div class="feature">
           <div class="feature-icon">🔄</div>
-          <h3>账号池高可用</h3>
-          <p>支持多账号自动调度与 failover。某个上游触发限流 / 冷却时，流量切到下一个健康账号，token 刷新全自动。</p>
+          <h3>{{ $t('landing.features.f2Title') }}</h3>
+          <p>{{ $t('landing.features.f2Desc') }}</p>
           <ul class="feature-bullets">
-            <li>限流/5xx 自动 failover</li>
-            <li>OAuth token 自动刷新</li>
-            <li>加权轮询 · 最少连接</li>
+            <li>{{ $t('landing.features.f2b1') }}</li>
+            <li>{{ $t('landing.features.f2b2') }}</li>
+            <li>{{ $t('landing.features.f2b3') }}</li>
           </ul>
         </div>
         <div class="feature">
           <div class="feature-icon">📊</div>
-          <h3>用量看板</h3>
-          <p>每条请求的 tokens、费用、上游账号、延迟全可视化。模型分布饼图 + 趋势曲线 + Top 排行。</p>
+          <h3>{{ $t('landing.features.f3Title') }}</h3>
+          <p>{{ $t('landing.features.f3Desc') }}</p>
           <ul class="feature-bullets">
-            <li>逐请求审计日志</li>
-            <li>多维度 tokens / cost 统计</li>
-            <li>导出 CSV / 接 Webhook</li>
+            <li>{{ $t('landing.features.f3b1') }}</li>
+            <li>{{ $t('landing.features.f3b2') }}</li>
+            <li>{{ $t('landing.features.f3b3') }}</li>
           </ul>
         </div>
       </div>
@@ -151,9 +158,13 @@
     <!-- ④ Code Demo -->
     <section class="block container" id="code">
       <div class="section-header">
-        <div class="section-kicker">// integration</div>
-        <h2 class="section-title">把 base_url 一改，就能用</h2>
-        <p class="section-sub">兼容 OpenAI / Anthropic / Gemini SDK，<span class="text-puro-cyan">零代码改动</span></p>
+        <div class="section-kicker">{{ $t('landing.codeDemo.kicker') }}</div>
+        <h2 class="section-title">{{ $t('landing.codeDemo.title') }}</h2>
+        <p class="section-sub">
+          <i18n-t keypath="landing.codeDemo.sub" tag="span">
+            <template #highlight><span class="text-puro-cyan">{{ $t('landing.codeDemo.subHighlight') }}</span></template>
+          </i18n-t>
+        </p>
       </div>
       <div class="code-demo">
         <div class="code-block">
@@ -186,15 +197,15 @@ requires_openai_auth = <span class="kw">true</span></code></pre>
   -d <span class="str">'{"model":"gpt-5.4","input":"hello"}'</span></code></pre>
         </div>
       </div>
-      <div class="code-foot">支持 OpenAI Responses API · Anthropic Messages API · Gemini generateContent · 流式 SSE &amp; WebSocket</div>
+      <div class="code-foot">{{ $t('landing.codeDemo.foot') }}</div>
     </section>
 
     <!-- ⑤ Dashboard mockup -->
     <section class="block container" id="dashboard">
       <div class="section-header">
-        <div class="section-kicker">// observability</div>
-        <h2 class="section-title">每条请求都看得见</h2>
-        <p class="section-sub">不像第三方 API 池子那种"扣了多少不告诉你"——扣哪个账号、跑哪个模型、用了多少 tokens、上游响应几秒，一目了然。</p>
+        <div class="section-kicker">{{ $t('landing.dashboard.kicker') }}</div>
+        <h2 class="section-title">{{ $t('landing.dashboard.title') }}</h2>
+        <p class="section-sub">{{ $t('landing.dashboard.sub') }}</p>
       </div>
       <div class="dash-mock">
         <!-- browser chrome header -->
@@ -225,15 +236,15 @@ requires_openai_auth = <span class="kw">true</span></code></pre>
           <!-- main content -->
           <div class="dash-main">
             <div class="stat-row">
-              <div class="stat"><div class="stat-label">今日请求</div><div class="stat-value">1,842</div><div class="stat-delta">+12.3%</div></div>
-              <div class="stat"><div class="stat-label">输入 Tokens</div><div class="stat-value">2.1M</div><div class="stat-delta">+8.1%</div></div>
-              <div class="stat"><div class="stat-label">输出 Tokens</div><div class="stat-value">485K</div><div class="stat-delta">+15.6%</div></div>
-              <div class="stat"><div class="stat-label">今日费用</div><div class="stat-value">$1.23</div><div class="stat-delta down">-4.2%</div></div>
+              <div class="stat"><div class="stat-label">{{ $t('landing.dashboard.statToday') }}</div><div class="stat-value">1,842</div><div class="stat-delta">+12.3%</div></div>
+              <div class="stat"><div class="stat-label">{{ $t('landing.dashboard.statTokensIn') }}</div><div class="stat-value">2.1M</div><div class="stat-delta">+8.1%</div></div>
+              <div class="stat"><div class="stat-label">{{ $t('landing.dashboard.statTokensOut') }}</div><div class="stat-value">485K</div><div class="stat-delta">+15.6%</div></div>
+              <div class="stat"><div class="stat-label">{{ $t('landing.dashboard.statCost') }}</div><div class="stat-value">$1.23</div><div class="stat-delta down">-4.2%</div></div>
             </div>
             <div class="chart-grid">
               <div class="chart-card">
                 <div class="chart-title">
-                  近 30 天用量趋势
+                  {{ $t('landing.dashboard.chartTrend') }}
                   <div class="chart-legend">
                     <span><span class="sw" style="background: var(--cyan)"></span> Claude</span>
                     <span><span class="sw" style="background: #a855f7"></span> GPT</span>
@@ -278,7 +289,7 @@ requires_openai_auth = <span class="kw">true</span></code></pre>
             </div>
             <table class="log-table mono">
               <thead>
-                <tr><th>时间</th><th>模型</th><th>上游</th><th>状态</th><th>用量</th></tr>
+                <tr><th>{{ $t('landing.dashboard.tableTime') }}</th><th>{{ $t('landing.dashboard.tableModel') }}</th><th>{{ $t('landing.dashboard.tableUpstream') }}</th><th>{{ $t('landing.dashboard.tableStatus') }}</th><th>{{ $t('landing.dashboard.tableUsage') }}</th></tr>
               </thead>
               <tbody>
                 <tr><td>12:34:07</td><td>gpt-5.4</td><td><span class="provider gpt"><span class="dot"></span>ChatGPT #1</span></td><td class="status-200">200</td><td>2,341</td></tr>
@@ -302,24 +313,24 @@ requires_openai_auth = <span class="kw">true</span></code></pre>
             </svg>
             <span>PURO AI</span>
           </div>
-          <p class="footer-tagline">把多个 AI 订阅聚合成统一 API。<br>让「已经付过钱」的订阅真正为你工作。</p>
+          <p class="footer-tagline">{{ $t('landing.footer.tagline1') }}<br>{{ $t('landing.footer.tagline2') }}</p>
           <p class="footer-meta">© 2026 puro.im · MIT License<br>fork of Wei-Shaw/sub2api</p>
           <div class="footer-status"><span class="dot-green"></span>all systems operational</div>
         </div>
         <div class="footer-col">
-          <div class="footer-col-title">产品</div>
-          <a href="/docs">文档</a>
-          <a href="#features">功能</a>
-          <a href="https://git.puro.im/purovps/sub2api/commits/branch/main" target="_blank" rel="noopener noreferrer">更新日志</a>
+          <div class="footer-col-title">{{ $t('landing.footer.colProducts') }}</div>
+          <a href="/docs">{{ $t('landing.footer.linkDocs') }}</a>
+          <a href="#features">{{ $t('landing.footer.linkFeatures') }}</a>
+          <a href="https://git.puro.im/purovps/sub2api/commits/branch/main" target="_blank" rel="noopener noreferrer">{{ $t('landing.footer.linkChangelog') }}</a>
         </div>
         <div class="footer-col">
-          <div class="footer-col-title">账户</div>
-          <router-link to="/login">登录</router-link>
-          <router-link to="/register">注册</router-link>
+          <div class="footer-col-title">{{ $t('landing.footer.colAccount') }}</div>
+          <router-link to="/login">{{ $t('landing.footer.linkLogin') }}</router-link>
+          <router-link to="/register">{{ $t('landing.footer.linkRegister') }}</router-link>
           <a href="/dashboard">Dashboard</a>
         </div>
         <div class="footer-col">
-          <div class="footer-col-title">联系</div>
+          <div class="footer-col-title">{{ $t('landing.footer.colContact') }}</div>
           <a href="mailto:admin@puro.im">admin@puro.im</a>
           <a href="https://git.puro.im" target="_blank" rel="noopener noreferrer">git.puro.im</a>
           <a href="https://git.puro.im/purovps/sub2api" target="_blank" rel="noopener noreferrer">GitHub ↗</a>