feat: remove legacy alert rules, superseded by automations

Alert rules already auto-migrate into automations on boot and the old
engine stands down after. Deletes the rule/firing tables, routes, UI,
and AI tools; keeps notification channels since automations still use
them. Also fixes automations' notify step, which still called the
deleted repository.

src/ui/locales/translated/zh_CN.json

@@ -287,7 +287,6 @@
     "loading": "加载中...",
     "noData": "暂无数据",
     "allClear": "一切正常",
-    "acknowledgeAlert": "确认告警",
     "noPingUrls": "未配置 URL",
     "pingLabel": "标签",
     "addPingUrl": "添加 URL",
@@ -324,8 +323,6 @@
     "widgetMetricsChartDesc": "主机的历史 CPU、内存、磁盘或网络图表",
     "widgetHostGridName": "主机网格",
     "widgetHostGridDesc": "SSH 主机状态的网格视图",
-    "widgetAlertFeedName": "告警信息流",
-    "widgetAlertFeedDesc": "实时告警触发信息，支持确认操作",
     "widgetPingStatusName": "Ping 状态",
     "widgetPingStatusDesc": "一个或多个 URL 的 HTTP ping 状态",
     "widgetRecentActivityName": "近期活动",
@@ -747,7 +744,6 @@
     "portForwarding": "转发",
     "sftp": "SFTP",
     "connections": "连接",
-    "alerts": "告警",
     "serial": "串口",
     "keepSideMenuOpen": "保持菜单打开",
     "collapseSideMenu": "折叠菜单",
@@ -4890,21 +4886,6 @@
     "viewHistory": "查看历史"
   },
   "alerts": {
-    "tabFirings": "告警",
-    "tabRules": "规则",
-    "tabChannels": "通道",
-    "noFirings": "没有未确认告警",
-    "noRules": "未配置告警规则",
-    "noChannels": "未配置通知渠道",
-    "rulesDesc": "告警规则触发通知",
-    "channelsDesc": "告警通知的发送渠道",
-    "acknowledge": "确认告警",
-    "ackAll": "全部确认",
-    "allAcknowledged": "所有告警已确认",
-    "ackFailed": "确认告警失败",
-    "ackAllFailed": "确认所有告警失败",
-    "showAcknowledged": "显示全部",
-    "hideAcknowledged": "隐藏已确认",
     "addChannel": "添加渠道",
     "editChannel": "编辑渠道",
     "channelName": "名称",
@@ -4917,22 +4898,7 @@
     "ntfyTopic": "主题",
     "ntfyTopicRequired": "主题为必填项",
     "ntfyToken": "访问令牌（选填）",
-    "channelSaveFailed": "保存渠道失败",
-    "test": "测试",
-    "testSent": "测试通知已发送",
-    "testFailed": "测试通知失败",
-    "testFailedWithReason": "测试通知失败：{{reason}}",
-    "addRule": "添加告警规则",
-    "editRule": "编辑告警规则",
-    "ruleName": "规则名称",
-    "ruleNameRequired": "名称为必填项",
-    "triggerType": "触发条件",
-    "thresholdValue": "阈值（%）",
-    "durationSeconds": "持续时间（秒，0 表示立即触发）",
-    "cooldownMinutes": "冷却时间（分钟）",
-    "channels": "通知渠道",
-    "noChannelsHint": "请先在渠道标签页中添加渠道",
-    "ruleSaveFailed": "保存规则失败"
+    "channelSaveFailed": "保存渠道失败"
   },
   "ai": {
     "title": "助手",