Add push reminder job for expiring notice deadlines

"Automatische Warnungen bei Auslauf/Kündigungsfristen" was only a
passive dashboard view (GET /contracts/notice-deadlines, isUrgent
flag) — nobody gets notified unless the landlord happens to open the
cockpit. Adds a daily job (same pattern as dailyDunningJob.ts) that
pushes landlords/admins when a contract's notice deadline falls
within 30 days. Dedup is via the Notification history (payload.
contractId within a 14-day cooldown) rather than a new Contract
column, consistent with contracts.ts's existing "no extra model
needed" approach.

backend/package.json

@@ -12,6 +12,7 @@
     "dunning:run": "ts-node -r dotenv/config src/jobs/dailyDunningJob.ts",
     "cleaning-reminder:run": "ts-node -r dotenv/config src/jobs/cleaningReminderJob.ts",
     "trash-reminder:run": "ts-node -r dotenv/config src/jobs/trashReminderJob.ts",
+    "notice-deadline-reminder:run": "ts-node -r dotenv/config src/jobs/noticeDeadlineReminderJob.ts",
     "test:webhook": "ts-node -r dotenv/config scripts/send-test-webhook.ts",
     "prisma:generate": "prisma generate --schema=../prisma/schema.prisma",
     "prisma:migrate": "prisma migrate dev --schema=../prisma/schema.prisma",

backend/src/jobs/noticeDeadlineReminderJob.ts

@@ -0,0 +1,85 @@
+import 'dotenv/config';
+import { PrismaClient } from '@prisma/client';
+import { sendPushNotification } from '../services/notificationService';
+
+const prisma = new PrismaClient();
+
+const NOTIFICATION_TYPE = 'NOTICE_DEADLINE';
+// Keine Wiederholung innerhalb dieses Zeitraums je Vertrag, um den Vermieter
+// nicht täglich 30 Tage lang zu spammen (bewusst kein Extra-Feld auf Contract
+// nötig — analog contracts.ts prüfen wir stattdessen den Notification-Verlauf).
+const RESEND_COOLDOWN_DAYS = 14;
+
+function addMonths(date: Date, months: number): Date {
+  const d = new Date(date);
+  d.setMonth(d.getMonth() - months);
+  return d;
+}
+
+/**
+ * Täglicher Cron-Job (analog dailyDunningJob.ts): warnt Vermieter/Admin per
+ * Push, wenn bei einem aktiven, befristeten Vertrag die Kündigungsfrist
+ * innerhalb der nächsten 30 Tage abläuft (isUrgent-Logik aus
+ * routes/contracts.ts). Max. 1x je Vertrag pro RESEND_COOLDOWN_DAYS.
+ */
+export async function runNoticeDeadlineReminderJob(referenceDate: Date = new Date()) {
+  const contracts = await prisma.contract.findMany({
+    where: { isActive: true, endDate: { not: null } },
+    select: {
+      id: true,
+      endDate: true,
+      noticePeriodMonths: true,
+      user: { select: { fullName: true } },
+      room: { select: { roomNumber: true } },
+    },
+  });
+
+  const urgent = contracts.filter((c) => {
+    const noticeDeadline = addMonths(c.endDate!, c.noticePeriodMonths);
+    const daysUntil = Math.ceil((noticeDeadline.getTime() - referenceDate.getTime()) / (1000 * 60 * 60 * 24));
+    return daysUntil <= 30 && daysUntil >= 0;
+  });
+
+  const landlords = await prisma.user.findMany({ where: { role: { in: ['LANDLORD', 'ADMIN'] } } });
+  const cooldownStart = new Date(referenceDate);
+  cooldownStart.setDate(cooldownStart.getDate() - RESEND_COOLDOWN_DAYS);
+
+  let remindersSent = 0;
+  for (const contract of urgent) {
+    const recentlySent = await prisma.notification.findFirst({
+      where: {
+        type: NOTIFICATION_TYPE,
+        sentAt: { gte: cooldownStart },
+        payload: { path: ['contractId'], equals: contract.id },
+      },
+    });
+    if (recentlySent) continue;
+
+    await Promise.all(
+      landlords.map((landlord) =>
+        sendPushNotification({
+          userId: landlord.id,
+          type: NOTIFICATION_TYPE,
+          title: 'Kündigungsfrist läuft bald ab',
+          body: `Für ${contract.room.roomNumber} (${contract.user.fullName}) endet die Kündigungsfrist in Kürze.`,
+          payload: { contractId: contract.id },
+        }),
+      ),
+    );
+    remindersSent++;
+  }
+
+  return { remindersSent };
+}
+
+if (require.main === module) {
+  runNoticeDeadlineReminderJob()
+    .then((result) => {
+      console.log(`[noticeDeadlineReminderJob] ${result.remindersSent} Erinnerungen versendet.`);
+      return prisma.$disconnect();
+    })
+    .catch((err) => {
+      console.error('[noticeDeadlineReminderJob] Fehlgeschlagen:', err);
+      process.exit(1);
+    });
+}