feat(license): Pro 授权机制 — 离线许可码 + 免费版功能闸门

免费版:日志查询/部署管理/采集/用户管理/LDAP/设置;Pro(¥199 个人单实例永久 / ¥499 团队多实例永久):
日志分析、日志告警、智能运维(AI)、审计日志。
- 后端:HMAC-SHA256 离线许可码(签发 CLI / license --plan --edition --seats --customer --days;
  永久=days 0),GET /system/license + POST activate;RequirePro 闸门挂 metrics/ai/audit;
  过期自动回落免费;测试覆盖签发-校验/篡改/免费拒签
- 前端:菜单 Pro 项带锁标;四个 Pro 页面免费版渲染升级引导卡(功能清单+定价+页内激活);
  设置页新增授权区(版本/席位/到期/激活入口);license 词典中英
- domains 注册提升到 main.tsx 全局(修复 license 命名空间在未引 domains 的页面显示裸键)

frontend/src/i18n/locales/en/license.ts

@@ -0,0 +1,39 @@
+// Pro license (upgrade gate / settings section)
+export default {
+  title: 'License',
+  freeBadge: 'Free',
+  freeDesc: 'You are on the Free plan: log query, deployment management, users and LDAP are included. Log analysis, alerts, AI ops and audit log are Pro features.',
+  edition: 'Edition',
+  expiry: 'Valid until',
+  customer: 'Licensed to',
+  seats: 'Seats',
+  permanent: 'perpetual',
+  personalTitle: 'Personal',
+  teamTitle: 'Team',
+  keyPlaceholder: 'Enter license key to activate Pro…',
+  activate: 'Activate',
+  activating: 'Activating…',
+  activated: 'Pro activated — all features unlocked',
+  activateFailed: 'Activation failed',
+  gate: {
+    title: '{{feature}} is a Pro feature',
+    desc: 'Upgrade to Pro to unlock the full analytics suite. The Free plan keeps log query, deployment management and user/LDAP administration.',
+    keyPlaceholder: 'Paste license key…',
+    activate: 'Activate',
+    toSettings: 'Open settings',
+    freeHint: 'Free plan includes: log query / deployment management / users / LDAP',
+  },
+  features: {
+    log_analysis: 'Log Analysis',
+    log_alerts: 'Log Alerts',
+    ai_ops: 'AI Ops',
+    audit_log: 'Audit Log',
+  },
+  pricing: {
+    personalTitle: 'Personal',
+    personalDesc: '1 instance · personal & community use · community support',
+    teamTitle: 'Team',
+    teamDesc: 'Multiple instances · commercial use · priority support',
+    permanent: 'one-time',
+  },
+}