feat: modernize application — source, platform artifacts, CI/CD

- chore: ingest source code

108 files from https://github.com/spring-projects/spring-petclinic
- feat: add platform deployment artifacts
- feat: add CI/CD workflow automation

Dockerfile

@@ -0,0 +1,30 @@
+# Multi-stage Dockerfile for Spring Boot Application
+FROM maven:3.9-eclipse-temurin-17 AS build
+WORKDIR /app
+
+# Copy dependency files first for better caching
+COPY pom.xml .
+RUN mvn dependency:go-offline -B
+
+# Copy source code and build
+COPY src ./src
+RUN mvn clean package -DskipTests
+
+# Runtime stage - lean JRE for Spring Boot executable JAR (~200MB vs ~500MB Tomcat)
+FROM mcr.microsoft.com/openjdk/jdk:17-ubuntu
+WORKDIR /app
+
+# Create non-root user for security
+RUN groupadd -g 1001 appuser && useradd -u 1001 -g appuser -s /bin/sh appuser && \
+    chown -R appuser:appuser /app
+USER appuser
+
+COPY --from=build /app/target/*.jar app.jar
+
+EXPOSE 8080
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=30s --retries=3 \
+  CMD wget --no-verbose --tries=1 --spider http://localhost:8080/actuator/health || exit 1
+
+CMD ["java", "-jar", "app.jar"]