feat: Wiederkehrende Aufgaben-Vorlagen (recurring task templates)

Neue TaskTemplate-Entität mit YEARLY/MONTHLY/INTERVAL_DAYS-Wiederholung.
Fällige Aufgaben werden lazy bei GET /tasks erzeugt (Compare-and-Swap auf
nextDueDate), damit mehrere API-Replicas im Kubernetes-Cluster dieselbe
Vorlage nicht doppelt feuern - ohne zusätzliche Cron-Abhängigkeit.

Frontend: Verwaltungsseite unter /settings/task-templates zum Anlegen,
Auflisten und Deaktivieren von Vorlagen.

ApiCore-Backend/prisma/migrations/20260825031814_add_task_templates/migration.sql

@@ -0,0 +1,37 @@
+-- CreateEnum
+CREATE TYPE "TaskTemplateRecurrenceType" AS ENUM ('YEARLY', 'MONTHLY', 'INTERVAL_DAYS');
+
+-- AlterTable
+ALTER TABLE "Task" ADD COLUMN     "sourceTemplateId" TEXT;
+
+-- CreateTable
+CREATE TABLE "TaskTemplate" (
+    "id" TEXT NOT NULL,
+    "title" TEXT NOT NULL,
+    "description" TEXT,
+    "priority" "TaskPriority" NOT NULL DEFAULT 'NORMAL',
+    "assignedUserId" TEXT,
+    "createdByUserId" TEXT,
+    "recurrenceType" "TaskTemplateRecurrenceType" NOT NULL,
+    "recurrenceMonth" INTEGER,
+    "recurrenceDayOfMonth" INTEGER,
+    "intervalDays" INTEGER,
+    "nextDueDate" TIMESTAMP(3) NOT NULL,
+    "active" BOOLEAN NOT NULL DEFAULT true,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "TaskTemplate_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "TaskTemplate_active_nextDueDate_idx" ON "TaskTemplate"("active", "nextDueDate");
+
+-- AddForeignKey
+ALTER TABLE "Task" ADD CONSTRAINT "Task_sourceTemplateId_fkey" FOREIGN KEY ("sourceTemplateId") REFERENCES "TaskTemplate"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "TaskTemplate" ADD CONSTRAINT "TaskTemplate_assignedUserId_fkey" FOREIGN KEY ("assignedUserId") REFERENCES "User"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "TaskTemplate" ADD CONSTRAINT "TaskTemplate_createdByUserId_fkey" FOREIGN KEY ("createdByUserId") REFERENCES "User"("id") ON DELETE SET NULL ON UPDATE CASCADE;

ApiCore-Backend/prisma/schema.prisma

@@ -47,6 +47,8 @@ model User {
   stockMovements        StockMovement[]
   assignedTasks         Task[]                 @relation("TaskAssignee")
   createdTasks          Task[]                 @relation("TaskCreator")
+  assignedTaskTemplates TaskTemplate[]         @relation("TaskTemplateAssignee")
+  createdTaskTemplates  TaskTemplate[]         @relation("TaskTemplateCreator")
   colonyMoves           ColonyApiaryHistory[]
   auditLogs             AuditLog[]
   bottlingBatches       BottlingBatch[]
@@ -386,6 +388,8 @@ model Task {
   relatedId          String?
   sourceInspectionId String?
   sourceInspection   Inspection?     @relation(fields: [sourceInspectionId], references: [id])
+  sourceTemplateId   String?
+  sourceTemplate     TaskTemplate?   @relation(fields: [sourceTemplateId], references: [id])
   createdAt          DateTime        @default(now())
   completedAt        DateTime?
 
@@ -393,6 +397,37 @@ model Task {
   @@index([relatedType, relatedId])
 }
 
+enum TaskTemplateRecurrenceType {
+  YEARLY
+  MONTHLY
+  INTERVAL_DAYS
+}
+
+// Wiederkehrende Aufgaben-Vorlagen – erzeugen automatisch eine neue Task,
+// sobald nextDueDate erreicht ist (siehe TasksService.generateDueTasks).
+model TaskTemplate {
+  id                   String                     @id @default(cuid())
+  title                String
+  description          String?
+  priority             TaskPriority               @default(NORMAL)
+  assignedUserId       String?
+  assignedUser         User?                      @relation("TaskTemplateAssignee", fields: [assignedUserId], references: [id])
+  createdByUserId      String?
+  createdByUser        User?                      @relation("TaskTemplateCreator", fields: [createdByUserId], references: [id])
+  recurrenceType       TaskTemplateRecurrenceType
+  recurrenceMonth      Int?
+  recurrenceDayOfMonth Int?
+  intervalDays         Int?
+  nextDueDate          DateTime
+  active               Boolean                    @default(true)
+  createdAt            DateTime                   @default(now())
+  updatedAt            DateTime                   @updatedAt
+
+  generatedTasks Task[]
+
+  @@index([active, nextDueDate])
+}
+
 // ---------------------------------------------------------------------------
 // Varroamanagement (Abschnitt 4.10)
 // ---------------------------------------------------------------------------