feat(backend): Fütterungen-Modul (Modul 9)

FeedingsModule mit Erfassung, Colony-Historie und
Mengensummen-Endpunkt je Einheit.

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

@@ -0,0 +1,63 @@
+import { Injectable, NotFoundException } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+import { AuditLogService } from '../audit/audit-log.service';
+import { Feeding } from '../../generated/prisma';
+import { CreateFeedingDto } from './dto/create-feeding.dto';
+
+export interface FeedingSummaryEntry {
+  unit: string;
+  totalAmount: number;
+}
+
+@Injectable()
+export class FeedingsService {
+  constructor(
+    private readonly prisma: PrismaService,
+    private readonly auditLog: AuditLogService,
+  ) {}
+
+  async findAll(): Promise<Feeding[]> {
+    return this.prisma.feeding.findMany({ orderBy: { date: 'desc' } });
+  }
+
+  async findById(id: string): Promise<Feeding> {
+    const feeding = await this.prisma.feeding.findUnique({ where: { id } });
+    if (!feeding) {
+      throw new NotFoundException('Feeding not found');
+    }
+    return feeding;
+  }
+
+  async findByColony(colonyId: string): Promise<Feeding[]> {
+    return this.prisma.feeding.findMany({
+      where: { colonyId },
+      orderBy: { date: 'asc' },
+    });
+  }
+
+  async summaryByColony(colonyId: string): Promise<FeedingSummaryEntry[]> {
+    const grouped = await this.prisma.feeding.groupBy({
+      by: ['unit'],
+      where: { colonyId },
+      _sum: { amount: true },
+    });
+    return grouped.map((entry) => ({
+      unit: entry.unit,
+      totalAmount: entry._sum.amount ?? 0,
+    }));
+  }
+
+  async create(dto: CreateFeedingDto, actingUserId: string): Promise<Feeding> {
+    const feeding = await this.prisma.feeding.create({
+      data: { ...dto, date: new Date(dto.date), userId: actingUserId },
+    });
+    await this.auditLog.record({
+      entityType: 'Feeding',
+      entityId: feeding.id,
+      action: 'CREATE',
+      userId: actingUserId,
+      afterData: feeding,
+    });
+    return feeding;
+  }
+}