fix(docker): copy prisma schema before npm ci and ensure prisma client target dir exists

backend/Dockerfile

@@ -2,7 +2,6 @@ FROM node:20-alpine AS builder
 USER root
 RUN http_proxy=http://172.17.0.1:8888 https_proxy=http://172.17.0.1:8888 apk add --no-cache openssl || apk add --no-cache openssl || true
 WORKDIR /app
-ENV PRISMA_SKIP_POSTINSTALL_GENERATE=true
 
 # Optional: Use Nexus as npm registry (pass --build-arg NPM_REGISTRY=http://nexus:8081/repository/npm/)
 ARG NPM_REGISTRY=
@@ -13,9 +12,10 @@ RUN if [ -n "$NPM_REGISTRY" ]; then \
     fi
 
 COPY package*.json ./
+COPY prisma ./prisma/
 RUN npm ci --prefer-offline --no-audit
 COPY . .
-RUN mkdir -p /app/node_modules/.prisma && rm -rf dist && https_proxy=http://172.17.0.1:8888 http_proxy=http://172.17.0.1:8888 ./node_modules/.bin/prisma generate && npm run build
+RUN mkdir -p /app/node_modules/.prisma/client && rm -rf dist && https_proxy=http://172.17.0.1:8888 http_proxy=http://172.17.0.1:8888 ./node_modules/.bin/prisma generate && npm run build
 
 FROM node:20-alpine
 USER root