feat(ops): alert on filesystem fill levels from the host worker

Add a pure df parser (disk-usage.ts) with 85/90/95% threshold classification, a diskPressure() alert (Discord/email/alert_logs, severity escalates with fill), and a 5-minute host-side probe in jobs-worker.ts that raises one alert per crossing mount, cooldown-gated per mount+level. Real mounts only: overlay/tmpfs pseudo filesystems are ignored.

src/lib/services/alert.ts

@@ -2,6 +2,7 @@ import { env } from "@/env";
 import { AlertLogs, db } from "@/lib/db";
 import { logger } from "@/lib/logger";
 import { sendMail } from "@/lib/services/email";
+import { diskLevel, formatBytes } from "./disk-usage";
 
 // === Alert service (AtomCMS → Next.js) ===========================================
 //
@@ -274,3 +275,38 @@ export function ddosDetected(
 		context: { ip, count },
 	});
 }
+
+/**
+ * Raise a WARNING/ERROR/CRITICAL alert when a filesystem crosses a fill
+ * threshold (see DISK_THRESHOLDS in disk-usage.ts): 85% warning, 90% error,
+ * 95% critical. Includes the offending mount and a pointer to the Docker prune.
+ */
+export function diskPressure(usage: {
+	filesystem: string;
+	mount: string;
+	totalBytes: number;
+	usedBytes: number;
+	availableBytes: number;
+	percent: number;
+}): Promise<SendAlertResult> {
+	const level = diskLevel(usage.percent);
+	const severity: AlertSeverity =
+		level >= 3 ? "critical" : level === 2 ? "error" : "warning";
+	return sendAlert({
+		type: "disk",
+		severity,
+		message:
+			`Disk ${level >= 3 ? "CRITICAL" : level === 2 ? "degraded" : "high"}: ` +
+			`${usage.mount} is ${usage.percent}% full ` +
+			`(${formatBytes(usage.usedBytes)} of ${formatBytes(usage.totalBytes)} used).`,
+		context: {
+			mount: usage.mount,
+			filesystem: usage.filesystem,
+			percentUsed: usage.percent,
+			used: formatBytes(usage.usedBytes),
+			total: formatBytes(usage.totalBytes),
+			available: formatBytes(usage.availableBytes),
+			hint: "Docker prune runs nightly; run scripts/docker-prune.sh to reclaim cache sooner.",
+		},
+	});
+}