update backend building

backend/Dockerfile

@@ -12,8 +12,8 @@ RUN apk add --no-cache python3 make g++
 # Copy package files for dependency installation
 COPY package*.json ./
 
-# Install all dependencies (including devDependencies for building)
-RUN npm ci
+# Install all dependencies including devDependencies regardless of NODE_ENV
+RUN npm ci --include=dev
 
 # Expose local binaries (e.g. tsc) to the shell PATH so npm run build resolves them
 ENV PATH="/app/node_modules/.bin:$PATH"