fix PrismaClient constructor: pass empty object (required prisma v7)

backend/Dockerfile

@@ -3,7 +3,8 @@ WORKDIR /app
 COPY package*.json ./
 RUN npm install
 COPY . .
-RUN npx prisma generate && npm run build
+RUN npx prisma generate
+RUN npm run build
 
 FROM node:22-alpine AS runner
 WORKDIR /app

backend/src/prisma/prisma.service.ts

@@ -4,7 +4,7 @@ import { PrismaClient } from '@prisma/client';
 @Injectable()
 export class PrismaService extends PrismaClient implements OnModuleInit, OnModuleDestroy {
   constructor() {
-    super({ datasources: { db: { url: process.env.DATABASE_URL } } });
+    super({});
   }
 
   async onModuleInit() {