fix(ume): global clear-push setting, schema migration, and help hints

Make forward-on-clear a global monitor toggle, run key-alert DDL in an
isolated startup transaction, and fix HelpHint popovers plus API errors
when the server returns non-JSON responses.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/i18n/en.ts

@@ -353,7 +353,7 @@ const en = {
       label: "Rule description",
       labelPh: "Required, e.g. BGP Down",
       forwardOnClear: "Push on alarm clear",
-      forwardOnClearHelp: "By default only new/updated alarms are pushed. When enabled, a clear notification is also sent when UME reports the alarm cleared.",
+      forwardOnClearHelp: "Global switch for all monitor rules. By default only new/updated alarms are pushed; when enabled, clear notifications are also sent when UME reports alarms cleared.",
       add: "Add rules",
       adding: "Adding…",
       delete: "Delete",

web/src/i18n/zh.ts

@@ -351,7 +351,7 @@ const zh = {
       label: "规则描述",
       labelPh: "必填，如 BGP Down",
       forwardOnClear: "告警清除时也推送",
-      forwardOnClearHelp: "默认只在告警新增/更新时推送。勾选后，当 UME 上报告警已清除（从当前告警表删除）时，也会向 WhatsApp 发送一条清除通知。",
+      forwardOnClearHelp: "全局开关：对所有监控规则生效。默认只在告警新增/更新时推送；勾选后，UME 上报告警已清除时也会向 WhatsApp 发送清除通知。",
       add: "添加规则",
       adding: "添加中…",
       delete: "删除",