DONE: update backend dockerfile build failed to use official maven instead of lightweight

be/Dockerfile

@@ -1,19 +1,20 @@
 # Build stage
-FROM maven:3.9-eclipse-temurin-17-alpine AS build
+# Non-alpine tags are multi-arch (amd64 + arm64). Alpine Maven often has no Mac/ARM image.
+FROM maven:3.9-eclipse-temurin-17 AS build
 WORKDIR /app
 
 COPY pom.xml .
-COPY mvnw .
-COPY .mvn .mvn
 COPY src ./src
 
-RUN ./mvnw -q -DskipTests package
+# Use image mvn (not ./mvnw). Official maven image sets MAVEN_CONFIG=/root/.m2,
+# which breaks the wrapper with: Unknown lifecycle phase "/root/.m2"
+RUN mvn -q -DskipTests package
 
 # Runtime stage
-FROM eclipse-temurin:17-jre-alpine
+FROM eclipse-temurin:17-jre
 WORKDIR /app
 
-RUN addgroup -S qms && adduser -S qms -G qms \
+RUN groupadd -r qms && useradd -r -g qms qms \
     && mkdir -p /app/uploads/ads \
     && chown -R qms:qms /app