feat: публичные лендинг-страницы для быстрой покупки VPN-подписок

- QuickPurchase: публичная страница покупки с выбором тарифа/периода/оплаты
- PurchaseSuccess: статус покупки с поллингом и копированием ссылки
- AdminLandings: управление лендингами (создание, сортировка, удаление)
- AdminLandingEditor: полнофункциональный редактор лендинга
- API-клиент landings.ts для всех эндпоинтов
- Роутинг /buy/:slug и /buy/success/:token
- Локализация ru/en/zh/fa для всех текстов лендинга
- Санитизация HTML/CSS, rate limit защита, DOMPurify

src/locales/zh.json

@@ -866,7 +866,8 @@
       "roleAssign": "角色分配",
       "policies": "访问策略",
       "auditLog": "审计日志",
-      "salesStats": "销售统计"
+      "salesStats": "销售统计",
+      "landings": "落地页"
     },
     "panel": {
       "title": "管理面板",
@@ -899,7 +900,8 @@
       "roleAssignDesc": "分配和撤销用户角色",
       "policiesDesc": "配置ABAC访问控制策略",
       "auditLogDesc": "查看系统活动和访问历史",
-      "salesStatsDesc": "销售分析与趋势"
+      "salesStatsDesc": "销售分析与趋势",
+      "landingsDesc": "快速购买落地页"
     },
     "salesStats": {
       "title": "销售统计",
@@ -2863,6 +2865,51 @@
         "loadFailed": "加载审计日志失败",
         "retry": "重试"
       }
+    },
+    "landings": {
+      "title": "落地页",
+      "create": "创建落地页",
+      "edit": "编辑",
+      "slug": "URL标识符",
+      "slugHint": "小写字母、数字和连字符",
+      "pageTitle": "标题",
+      "subtitle": "副标题",
+      "footerText": "底部文本 (HTML)",
+      "features": "功能特点",
+      "addFeature": "添加",
+      "featureIcon": "图标",
+      "featureTitle": "标题",
+      "featureDesc": "描述",
+      "tariffs": "套餐",
+      "selectTariffs": "选择套餐",
+      "periods": "周期",
+      "paymentMethods": "支付方式",
+      "addMethod": "添加方式",
+      "methodId": "方式ID",
+      "methodName": "名称",
+      "methodDesc": "描述",
+      "methodIcon": "图标URL",
+      "gifts": "礼物",
+      "giftEnabled": "礼物购买",
+      "customCss": "CSS",
+      "seo": "SEO",
+      "metaTitle": "Meta标题",
+      "metaDesc": "Meta描述",
+      "active": "已激活",
+      "inactive": "未激活",
+      "purchases": "次购买",
+      "copyUrl": "复制URL",
+      "urlCopied": "URL已复制",
+      "deleteConfirm": "删除落地页「{{title}}」？",
+      "created": "落地页已创建",
+      "updated": "落地页已更新",
+      "deleted": "落地页已删除",
+      "saveOrder": "保存排序",
+      "orderSaved": "排序已保存",
+      "general": "基本设置",
+      "content": "内容",
+      "save": "保存",
+      "back": "返回"
     }
   },
   "adminUpdates": {
@@ -3415,5 +3462,44 @@
     "error": "合并失败，请稍后重试。",
     "expiresIn": "剩余 {{minutes}} 分钟",
     "merging": "合并中..."
+  },
+  "landing": {
+    "notFound": "页面未找到",
+    "forMe": "为自己",
+    "asGift": "作为礼物",
+    "contactLabel": "您的邮箱或 @用户名",
+    "yourContact": "您的邮箱或 @用户名",
+    "contactPlaceholder": "email@example.com 或 @username",
+    "contactHint": "输入邮箱或 Telegram @用户名",
+    "recipientLabel": "赠送对象",
+    "recipientPlaceholder": "收件人邮箱或 @用户名",
+    "giftMessageLabel": "祝福语（可选）",
+    "giftMessagePlaceholder": "写一段祝福语...",
+    "chooseTariff": "选择套餐",
+    "devices": "设备",
+    "paymentMethod": "支付方式",
+    "processing": "处理中...",
+    "payButton": "支付 {{price}}",
+    "accessFor": "{{period}} 访问权限",
+    "purchaseError": "创建支付失败",
+    "purchaseNotFound": "未找到购买记录",
+    "awaitingPayment": "等待支付",
+    "awaitingPaymentDesc": "请在打开的窗口中完成支付",
+    "purchaseSuccess": "支付成功！",
+    "keySentTo": "订阅密钥已发送至 {{contact}}",
+    "giftSentTo": "礼物已发送至 {{contact}}",
+    "purchaseFailed": "支付失败",
+    "purchaseFailedDesc": "支付未成功，请重试。",
+    "subscriptionLink": "订阅链接",
+    "daysAccess": "天访问权限",
+    "error": "错误",
+    "gb": "GB",
+    "selectedTariff": "套餐",
+    "period": "时长",
+    "total": "总计",
+    "pay": "支付",
+    "choosePeriod": "选择时长",
+    "copied": "已复制！",
+    "copyLink": "复制链接"
   }
 }