feat(backend): Dashboard-Modul (Modul 13)

DashboardModule mit Kennzahlen-Übersicht sowie Alerts fuer
überfällige Aufgaben, auffällige Völker und Lagerartikel unter
Mindestbestand.

ApiCore-Backend/src/dashboard/dashboard.service.ts

@@ -0,0 +1,107 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+
+export interface DashboardSummary {
+  apiariesActive: number;
+  coloniesActive: number;
+  queensActive: number;
+  openTasks: number;
+  honeyBatchesTotal: number;
+  stockItemsLowCount: number;
+}
+
+export interface DashboardAlert {
+  type: 'OVERDUE_TASK' | 'COLONY_ATTENTION' | 'LOW_STOCK';
+  message: string;
+  relatedType: string;
+  relatedId: string;
+}
+
+const ATTENTION_COLONY_STATUSES = ['WEAK', 'QUEENLESS', 'CONSPICUOUS'] as const;
+
+@Injectable()
+export class DashboardService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  async summary(): Promise<DashboardSummary> {
+    const [
+      apiariesActive,
+      coloniesActive,
+      queensActive,
+      openTasks,
+      honeyBatchesTotal,
+      stockItems,
+    ] = await Promise.all([
+      this.prisma.apiary.count({ where: { status: 'ACTIVE' } }),
+      this.prisma.colony.count({ where: { status: 'ACTIVE' } }),
+      this.prisma.queen.count({
+        where: { status: { in: ['ACTIVE', 'RESERVE'] } },
+      }),
+      this.prisma.task.count({
+        where: { status: { in: ['OPEN', 'IN_PROGRESS'] } },
+      }),
+      this.prisma.honeyBatch.count(),
+      this.prisma.stockItem.findMany({
+        where: { minThreshold: { not: null } },
+      }),
+    ]);
+    const stockItemsLowCount = stockItems.filter(
+      (item) => item.minThreshold !== null && item.quantity < item.minThreshold,
+    ).length;
+
+    return {
+      apiariesActive,
+      coloniesActive,
+      queensActive,
+      openTasks,
+      honeyBatchesTotal,
+      stockItemsLowCount,
+    };
+  }
+
+  async alerts(): Promise<DashboardAlert[]> {
+    const [overdueTasks, attentionColonies, stockItems] = await Promise.all([
+      this.prisma.task.findMany({
+        where: {
+          status: { in: ['OPEN', 'IN_PROGRESS'] },
+          dueDate: { lt: new Date() },
+        },
+      }),
+      this.prisma.colony.findMany({
+        where: { status: { in: [...ATTENTION_COLONY_STATUSES] } },
+      }),
+      this.prisma.stockItem.findMany({
+        where: { minThreshold: { not: null } },
+      }),
+    ]);
+
+    const alerts: DashboardAlert[] = [];
+    for (const task of overdueTasks) {
+      alerts.push({
+        type: 'OVERDUE_TASK',
+        message: `Aufgabe "${task.title}" ist überfällig`,
+        relatedType: 'Task',
+        relatedId: task.id,
+      });
+    }
+    for (const colony of attentionColonies) {
+      alerts.push({
+        type: 'COLONY_ATTENTION',
+        message: `Volk ${colony.code} benötigt Aufmerksamkeit (${colony.status})`,
+        relatedType: 'Colony',
+        relatedId: colony.id,
+      });
+    }
+    for (const item of stockItems) {
+      if (item.minThreshold !== null && item.quantity < item.minThreshold) {
+        alerts.push({
+          type: 'LOW_STOCK',
+          message: `Lagerartikel "${item.name}" unter Mindestbestand`,
+          relatedType: 'StockItem',
+          relatedId: item.id,
+        });
+      }
+    }
+    return alerts;
+  }
+}