feat(backend): Ernten- und Schleuderungs-Module (Modul 10)

HarvestsModule und ExtractionsModule als Fundament der
Rückverfolgbarkeitskette: eine Ernte kann mehrere Völker umfassen,
eine Schleuderung mehrere Ernten zusammenführen.

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

@@ -0,0 +1,69 @@
+import { Injectable, NotFoundException } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+import { AuditLogService } from '../audit/audit-log.service';
+import { CreateExtractionDto } from './dto/create-extraction.dto';
+
+const extractionInclude = {
+  harvests: {
+    include: {
+      harvest: { include: { colonies: { include: { colony: true } } } },
+    },
+  },
+} as const;
+
+@Injectable()
+export class ExtractionsService {
+  constructor(
+    private readonly prisma: PrismaService,
+    private readonly auditLog: AuditLogService,
+  ) {}
+
+  async findAll() {
+    return this.prisma.extraction.findMany({
+      include: extractionInclude,
+      orderBy: { date: 'desc' },
+    });
+  }
+
+  async findById(id: string) {
+    const extraction = await this.prisma.extraction.findUnique({
+      where: { id },
+      include: extractionInclude,
+    });
+    if (!extraction) {
+      throw new NotFoundException('Extraction not found');
+    }
+    return extraction;
+  }
+
+  async create(dto: CreateExtractionDto, actingUserId: string) {
+    const extraction = await this.prisma.$transaction(async (tx) => {
+      const created = await tx.extraction.create({
+        data: {
+          date: new Date(dto.date),
+          amount: dto.amount,
+          room: dto.room,
+          waterContent: dto.waterContent,
+          temperature: dto.temperature,
+          notes: dto.notes,
+          userId: actingUserId,
+        },
+      });
+      await tx.extractionHarvest.createMany({
+        data: dto.harvestIds.map((harvestId) => ({
+          extractionId: created.id,
+          harvestId,
+        })),
+      });
+      return created;
+    });
+    await this.auditLog.record({
+      entityType: 'Extraction',
+      entityId: extraction.id,
+      action: 'CREATE',
+      userId: actingUserId,
+      afterData: extraction,
+    });
+    return this.findById(extraction.id);
+  }
+}