Surface Proxmox backup job status, with a daily failure notification

Proxmox already runs vzdump backups, but nothing in the app said
whether they were actually succeeding — a silent backup failure is
one of the more dangerous blind spots a homelab admin can have. Adds
a "Backups" card to the Proxmox page: configured backup job
schedules (storage target, which guests, enabled/disabled) from
GET /cluster/backup, and recent vzdump task history per node from
GET /nodes/{node}/tasks?typefilter=vzdump, with a banner at the top
if the most recent run didn't succeed.

New "Proxmox backup failed" notification toggle under Settings ->
Notifications, on the same daily schedule as the other checks. The
scheduler checks each node's own most-recent vzdump run independently
(not just the single most recent task overall) so one node's healthy
backup can't mask another node's failing one in a multi-node cluster.

Known limitation, documented in the adapter's own header comment:
Proxmox's task list doesn't reliably expose which specific guest
failed within an "all guests" job — only the task's own log text has
that — so this surfaces job- and task-level status rather than
guessing at per-guest outcomes.

Verified against a fake Proxmox server (real self-signed HTTPS, since
the adapter's node:https usage can't be monkey-patched under ESM)
reproducing the documented /cluster/backup and task-list response
shapes: job parsing (all-guests+exclude vs specific-vmids+disabled)
correct, task OK/failure parsing correct, and the critical multi-node
scenario confirmed — one node's failing latest run flagged, the
other's healthy latest run correctly left alone, with exactly one
notification of the right content. This reproduces Proxmox's
documented API shape rather than a live-verified one; flag if the
real cluster's response differs in some way this didn't anticipate.
Confirmed the real dev database's mtime was untouched throughout.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/pages/settings/NotificationSettings.tsx

@@ -43,6 +43,7 @@ const DEFAULT_NOTIFICATIONS: NotificationEvents = {
   secretCheck: true,
   tailscaleKeyCheck: true,
   dockerUpdateCheck: true,
+  proxmoxBackupCheck: true,
   secretCheckTime: "08:00",
   timezone: "UTC",
   integrationFailureAlerts: true,
@@ -493,6 +494,7 @@ export default function NotificationSettings() {
                 { key: "secretCheck" as const, label: "Secret expiry reminder" },
                 { key: "tailscaleKeyCheck" as const, label: "Tailscale key expiry reminder" },
                 { key: "dockerUpdateCheck" as const, label: "Docker image update available" },
+                { key: "proxmoxBackupCheck" as const, label: "Proxmox backup failed" },
                 { key: "integrationFailureAlerts" as const, label: "Integration/DNS provider failing repeatedly" },
               ].map(({ key, label }) => (
                 <label key={key} className="form-check mb-2">
@@ -526,7 +528,8 @@ export default function NotificationSettings() {
                 </div>
               </div>
               {(() => {
-                const dailyChecksEnabled = notifications.secretCheck || notifications.tailscaleKeyCheck || notifications.dockerUpdateCheck;
+                const dailyChecksEnabled =
+                  notifications.secretCheck || notifications.tailscaleKeyCheck || notifications.dockerUpdateCheck || notifications.proxmoxBackupCheck;
                 return (
                   <div className="row g-2 mt-2">
                     <div className="col-6">
@@ -538,7 +541,7 @@ export default function NotificationSettings() {
                         disabled={!dailyChecksEnabled}
                         onChange={(e) => setNotifications((n) => ({ ...n, secretCheckTime: e.target.value }))}
                       />
-                      <div className="form-hint">Shared by the secret, Tailscale key, and Docker update reminders above.</div>
+                      <div className="form-hint">Shared by the secret, Tailscale key, Docker update, and Proxmox backup reminders above.</div>
                     </div>
                     <div className="col-6">
                       <label className="form-label">Timezone</label>