fix(Dockerfile): add debug tools

Dockerfile

@@ -12,6 +12,15 @@ RUN --mount=type=cache,target=/root/.m2 mvn -B -q package -DskipTests
 # ===== runtime stage =====
 FROM harbor.merlin.xin/mirrors/docker.io/library/eclipse-temurin:17-jre-alpine
 
+# >>> Install debug tools <<<
+RUN apk update && apk add --no-cache \
+    curl \
+    bind-tools \
+    busybox-extras \
+    iproute2 \
+    tcpdump \
+    net-tools
+
 WORKDIR /app
 COPY --from=builder /app/target/*.jar app.jar
 
@@ -20,8 +29,6 @@ RUN addgroup -S spring && adduser -S spring -G spring
 RUN mkdir -p /app/uploads/photo \
  && chown -R spring:spring /app/uploads
 
-
 USER spring
 
-ENTRYPOINT ["java","-jar","/app/app.jar", "--spring.config.location=file:/app/application.yml"]
-
+ENTRYPOINT ["java","-jar","/app/app.jar","--spring.config.location=file:/app/application.yml"]