fix(backup-dashboard): show last SUCCESSFUL backup + last attempt separately

The dashboard widget used `lastBackup.created_at` for the "Last
successful backup: X ago" text — but lastBackup is the most recent
row of any status. So a crashed restore (status=running, never
updated) or a recent failure showed up labeled as the last
successful backup. Same "silent failure not surfaced" class the
restore wizard had.

Backend now returns:
  lastSuccessfulBackup — most recent backup_runs with status='completed'
  zombieRuns — running rows older than 30 min (likely crashed mid-flight)
  lastBackup — unchanged (most recent any status)

Frontend renders:
  - "Last successful backup: X ago"  — always from lastSuccessfulBackup
  - "Last attempt: Y ago · failed/running"  — when lastBackup differs
    from lastSuccessful. failed shows the first line of error_message
    in red; running stays neutral.
  - Zombie callout — "N backup(s) running >30min — may have crashed"
    in amber, so admin sees stuck rows at a glance.
  - Health score downgrades from "excellent" to "warning" if the
    latest attempt failed, even when older successes keep the age
    fresh — surfaces regressions without erasing the green history.

backend/src/services/backupService.js

@@ -1237,11 +1237,34 @@ async function getBackupStatus(limit = 10) {
 
     const lastRunWithManifest = lastRun ? { ...lastRun, manifestValid } : null;
 
+    // Separate "most recent attempt" from "most recent SUCCESS" so the
+    // dashboard widget can distinguish:
+    //   - last attempt failed → red, "Last attempt failed at X"
+    //   - last attempt running → blue spinner, "In progress since X"
+    //   - never succeeded → critical, "No successful backup yet"
+    //   - last attempt succeeded → green tick, "Last backup X ago"
+    // Previously the widget showed the most-recent row with a generic
+    // green tick regardless of status, so a crashed run from 5 minutes
+    // ago looked identical to a successful one. Same "silent failure
+    // not surfaced" class Stage A was designed to fight.
+    const lastSuccessful = runs.find(r => r.status === 'completed') || null;
+    // Detect zombie running rows (started >30min ago, never updated)
+    // — these are processes that died without writing a completed_at.
+    // Surface them so the admin can tell at a glance vs a live run.
+    const ZOMBIE_THRESHOLD_MS = 30 * 60 * 1000;
+    const zombieRuns = runs.filter(r =>
+      r.status === 'running'
+      && r.started_at
+      && (Date.now() - new Date(r.started_at).getTime()) > ZOMBIE_THRESHOLD_MS
+    );
+
     return {
       isRunning,
       isHealthy: Boolean(lastRun && lastRun.status === 'completed'),
       lastRun: lastRunWithManifest,
       lastBackup: lastRunWithManifest, // Alias for frontend compatibility
+      lastSuccessfulBackup: lastSuccessful, // NEW — see comment above
+      zombieRuns,                           // NEW — running >30min, likely crashed
       recentRuns: runs,
       recentBackups: runs, // Alias for frontend compatibility
       totalBackups: runs.filter(r => r.status === 'completed').length,

frontend/src/components/admin/BackupDashboard.tsx

@@ -38,11 +38,15 @@ interface BackupRecord {
   backup_type: string;
   created_at: string;
   duration_seconds: number;
+  started_at?: string;
+  error_message?: string;
   statistics?: BackupStatistics;
 }
 
 interface BackupStatus {
-  lastBackup?: BackupRecord;
+  lastBackup?: BackupRecord;             // most recent attempt, any status
+  lastSuccessfulBackup?: BackupRecord;   // most recent completed run
+  zombieRuns?: BackupRecord[];           // running > 30min, likely crashed
   totalBackups?: number;
   recentBackups?: BackupRecord[];
 }
@@ -105,18 +109,40 @@ const healthColors: Record<HealthStatus, string> = {
 
 export const BackupDashboard: React.FC<BackupDashboardProps> = ({ status, config, onRunBackup, isBackupRunning }) => {
   const { t } = useTranslation();
-  const lastBackup = status?.lastBackup;
-  const statistics = lastBackup?.statistics ?? {};
+  const lastBackup = status?.lastBackup;                       // any status
+  const lastSuccessfulBackup = status?.lastSuccessfulBackup;   // status='completed' only
+  const zombieRuns = status?.zombieRuns ?? [];
+  const statistics = lastSuccessfulBackup?.statistics ?? lastBackup?.statistics ?? {};
   const isConfigured = config && config.backup_destination_type;
   const isEnabled = config?.backup_enabled;
 
+  // Use the most recent SUCCESSFUL backup as the "age" reference for
+  // health, so a transient failure doesn't immediately drop the score
+  // — but call out failed/running/zombie attempts explicitly so the
+  // admin sees them at a glance.
   const getHealthScore = (): { score: number; status: HealthStatus; message: string } => {
-    if (!lastBackup) return { score: 0, status: 'critical', message: t('backup.dashboard.healthMessages.noBackups') };
+    if (!lastSuccessfulBackup) {
+      // No successful backup ever recorded.
+      if (lastBackup?.status === 'failed') {
+        return { score: 0, status: 'critical', message: t('backup.dashboard.healthMessages.lastBackupFailed') };
+      }
+      return { score: 0, status: 'critical', message: t('backup.dashboard.healthMessages.noBackups') };
+    }
 
-    const hoursSinceBackup = (Date.now() - new Date(lastBackup.created_at).getTime()) / (1000 * 60 * 60);
+    const hoursSinceBackup = (Date.now() - new Date(lastSuccessfulBackup.created_at).getTime()) / (1000 * 60 * 60);
 
-    if (lastBackup.status === 'failed') {
-      return { score: 0, status: 'critical', message: t('backup.dashboard.healthMessages.lastBackupFailed') };
+    // A successful backup exists. Bias the score on its age, but if
+    // the MOST RECENT attempt failed, downgrade the message so the
+    // admin sees the regression even though older backups are fine.
+    const latestAttemptFailed = lastBackup && lastBackup.id !== lastSuccessfulBackup.id
+      && lastBackup.status === 'failed';
+
+    if (latestAttemptFailed) {
+      return {
+        score: 50,
+        status: 'warning',
+        message: t('backup.dashboard.healthMessages.lastBackupFailed'),
+      };
     }
 
     if (hoursSinceBackup < 24) {
@@ -190,9 +216,43 @@ export const BackupDashboard: React.FC<BackupDashboardProps> = ({ status, config
 
           <div className="flex-1">
             <p className="text-neutral-700 dark:text-neutral-300 font-medium">{health.message}</p>
-            {lastBackup && (
+            {/* Show the last successful backup explicitly — previously
+                this read `lastBackup.created_at` which silently rendered
+                a failed/running row as if it were the last success. */}
+            {lastSuccessfulBackup && (
               <p className="text-sm text-neutral-500 dark:text-neutral-400 mt-1">
-                Last successful backup: {formatDistanceToNow(new Date(lastBackup.created_at), { addSuffix: true })}
+                {t('backup.dashboard.lastSuccessful', 'Last successful backup')}: {formatDistanceToNow(new Date(lastSuccessfulBackup.created_at), { addSuffix: true })}
+              </p>
+            )}
+            {/* If the most recent attempt is NOT the last successful
+                run, surface it separately so the admin sees the
+                divergence (latest attempt failed or running). */}
+            {lastBackup && lastBackup.id !== lastSuccessfulBackup?.id && (
+              <p className={`text-sm mt-1 ${
+                lastBackup.status === 'failed'
+                  ? 'text-red-600 dark:text-red-400 font-medium'
+                  : lastBackup.status === 'running'
+                    ? 'text-blue-600 dark:text-blue-400'
+                    : 'text-neutral-500 dark:text-neutral-400'
+              }`}>
+                {t('backup.dashboard.lastAttempt', 'Last attempt')}: {formatDistanceToNow(new Date(lastBackup.created_at), { addSuffix: true })}
+                {' · '}
+                {t(`backup.dashboard.status.${lastBackup.status}`, lastBackup.status)}
+                {lastBackup.status === 'failed' && lastBackup.error_message && (
+                  <span className="block text-xs text-red-600 dark:text-red-400 mt-0.5">
+                    {lastBackup.error_message.split('\n')[0].slice(0, 200)}
+                  </span>
+                )}
+              </p>
+            )}
+            {/* Zombie warning — running >30min, almost certainly crashed.
+                Admin needs to know they may be looking at a hung row
+                that won't ever flip to completed. */}
+            {zombieRuns.length > 0 && (
+              <p className="text-sm mt-1 text-amber-700 dark:text-amber-300 font-medium">
+                {t('backup.dashboard.zombieRuns',
+                  '{{count}} backup(s) running >30min — may have crashed without completing',
+                  { count: zombieRuns.length })}
               </p>
             )}