feat(monitoring): add update-run log, fix scheduler skipping stale customer containers

The automatic scheduler only recreated customer containers when it had just
found a NEW image on Docker Hub. If an image was already pulled locally
(e.g. from an earlier manual pull, or auto-apply was off at the time) but
customer containers hadn't been recreated yet, the daily check reported
"already up to date" and silently never touched those customers again —
the recreate step needs to run independently of whether Hub had anything
new, based on each customer's actual container-vs-local-image state.

Also adds a persistent UpdateRunLog: every scheduled and manual pull/update
run now records per-image pull results and per-customer recreate results,
visible in Monitoring > Update Log, instead of only existing in container
logs.

static/lang/de.json

@@ -454,6 +454,25 @@
     "autoUpdateApplyHint": "Wenn aktiviert, werden nach einer gefundenen Aktualisierung automatisch alle Kunden-Container neu erstellt (kurzer Neustart der Dienste). Wenn deaktiviert, werden nur die Images geladen — die Aktualisierung der Kunden erfolgt weiterhin manuell.",
     "autoUpdateLastRun": "Letzte automatische Prüfung",
     "autoUpdateNever": "Noch nie ausgeführt",
-    "saveAutoUpdateSettings": "Automatisierung speichern"
+    "saveAutoUpdateSettings": "Automatisierung speichern",
+    "updateLogTitle": "Update-Verlauf",
+    "noUpdateLogs": "Noch keine Update-Läufe protokolliert.",
+    "logTypeScheduled": "Automatisch",
+    "logTypeManual": "Manuell",
+    "logTime": "Zeitpunkt",
+    "logType": "Typ",
+    "logPull": "Image-Download",
+    "logApply": "Kunden-Update",
+    "logTrigger": "Ausgelöst von",
+    "logPullOk": "Erfolgreich",
+    "logPullFailed": "Fehlgeschlagen",
+    "logPullSkipped": "Nicht nötig",
+    "logApplySummary": "{updated}/{total} Kunden",
+    "logApplySkipped": "Nicht ausgeführt",
+    "logStatus_success": "Erfolgreich",
+    "logStatus_no_update": "Kein Update nötig",
+    "logStatus_partial": "Teilweise",
+    "logStatus_failed": "Fehlgeschlagen",
+    "logStatus_running": "Läuft…"
   }
 }

static/lang/en.json

@@ -361,7 +361,26 @@
     "autoUpdateApplyHint": "When enabled, all customer containers are automatically recreated after a new image is found (services briefly restart). When disabled, only the images are pulled — updating customers stays a manual step.",
     "autoUpdateLastRun": "Last automatic check",
     "autoUpdateNever": "Never run",
-    "saveAutoUpdateSettings": "Save Automation"
+    "saveAutoUpdateSettings": "Save Automation",
+    "updateLogTitle": "Update Log",
+    "noUpdateLogs": "No update runs logged yet.",
+    "logTypeScheduled": "Automatic",
+    "logTypeManual": "Manual",
+    "logTime": "Time",
+    "logType": "Type",
+    "logPull": "Image Pull",
+    "logApply": "Customer Update",
+    "logTrigger": "Triggered by",
+    "logPullOk": "Succeeded",
+    "logPullFailed": "Failed",
+    "logPullSkipped": "Not needed",
+    "logApplySummary": "{updated}/{total} customers",
+    "logApplySkipped": "Not run",
+    "logStatus_success": "Success",
+    "logStatus_no_update": "No update needed",
+    "logStatus_partial": "Partial",
+    "logStatus_failed": "Failed",
+    "logStatus_running": "Running…"
   },
   "userModal": {
     "title": "New User",