feat: update Dockerfile stages for improved dependency management; add prisma to package.json and package-lock.json

backend/Dockerfile

@@ -1,33 +1,33 @@
 # Byggas från backend-mappen: docker build -t recipe-api:local .
 
-# Stage 1: Bygg applikationen
+# Stage 1: Installera enbart produktionsberoenden (exkl. devDeps)
+FROM node:24.15.0-alpine AS deps
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci --omit=dev
+RUN ./node_modules/.bin/prisma generate
+
+# Stage 2: Bygg applikationen (alla beroenden, kör tester)
 FROM node:24.15.0-alpine AS builder
 WORKDIR /app
-
-# Kopiera backend-filer
-COPY package.json ./
-COPY package-lock.json ./
+COPY package.json package-lock.json ./
+RUN npm ci
 COPY prisma ./prisma
 COPY src ./src
-COPY tsconfig.json ./
-COPY nest-cli.json ./
-
-# Köra npm ci för reproducerbara builds
-RUN npm ci
-
-RUN npx prisma generate
+COPY tsconfig.json nest-cli.json ./
+RUN ./node_modules/.bin/prisma generate
 RUN npm test
 RUN npm run build
 
-# Stage 2: Kör applikationen
+# Stage 3: Kör applikationen
 FROM node:24.15.0-alpine AS runner
 WORKDIR /app
 ENV NODE_ENV=production
 
-COPY --from=builder /app/package.json ./package.json
-COPY --from=builder /app/node_modules ./node_modules
+COPY package.json ./
+COPY --from=deps /app/node_modules ./node_modules
 COPY --from=builder /app/prisma ./prisma
 COPY --from=builder /app/dist ./dist
 
 EXPOSE 8080
-CMD ["sh", "-c", "until npx prisma migrate deploy; do echo 'Migration failed, retrying in 5s...'; sleep 5; done && node dist/main"]
+CMD ["sh", "-c", "until ./node_modules/.bin/prisma migrate deploy; do echo 'Migration failed, retrying in 5s...'; sleep 5; done && node dist/main"]