feat(ops): health-fail alerts, optional DB backup, admin UX polish

Wire jobs-worker health probes to Discord/email alerts with cooldown, optional mysqldump, rate-limit /api/health, mark-all-read alerts, ConfirmDialog on destructive admin actions, and raise coverage floors.

Co-authored-by: Cursor <[email protected]>

src/app/admin/alerts/page.tsx

@@ -1,7 +1,7 @@
 import { desc } from "drizzle-orm";
 import { redirect } from "next/navigation";
 import { getTranslations } from "next-intl/server";
-import { sendHotelAlert } from "@/actions/admin-alerts";
+import { markAllAlertsRead, sendHotelAlert } from "@/actions/admin-alerts";
 import { StatusCard } from "@/components/admin/dashboard";
 import { Button } from "@/components/ui/button";
 import { AlertLogs, db } from "@/lib/db";
@@ -125,7 +125,16 @@ export default async function AdminAlerts() {
 			</form>
 
 			<section className="admin-card">
-				<h3 className="mt-0">{t("recentAlerts", { count: alerts.length })}</h3>
+				<div className="mb-3 flex flex-wrap items-center justify-between gap-2">
+					<h3 className="m-0">{t("recentAlerts", { count: alerts.length })}</h3>
+					{unread > 0 ? (
+						<form action={markAllAlertsRead}>
+							<Button type="submit" variant="outline" size="sm">
+								{t("markAllRead")}
+							</Button>
+						</form>
+					) : null}
+				</div>
 				{alerts.length === 0 ? (
 					<div className="admin-empty">{t("noAlerts")}</div>
 				) : (