Add Dockerfile back to customer repo

Dockerfile is customer-owned. docker-compose.yml and clouderized.yaml
are operator-generated and live outside the customer repo.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,33 @@
+# === Build stage ===
+FROM eclipse-temurin:25-jdk AS build
+
+RUN apt-get update && apt-get install -y curl gnupg && \
+    curl -sL "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x2EE0EA64E40A89B84B2DF73499E82A75642AC823" | gpg --dearmor > /etc/apt/trusted.gpg.d/sbt.gpg && \
+    echo "deb https://repo.scala-sbt.org/scalasbt/debian all main" > /etc/apt/sources.list.d/sbt.list && \
+    apt-get update && apt-get install -y sbt && \
+    rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY build.sbt .
+COPY project/*.sbt project/*.properties project/*.scala project/
+RUN sbt update
+
+COPY src/ src/
+RUN sbt "set test in assembly := false" assembly
+
+# === Runtime stage ===
+FROM eclipse-temurin:25-jre-alpine
+
+RUN addgroup -S app && adduser -S app -G app
+WORKDIR /app
+
+COPY --from=build --chown=app:app /app/target/scala-3.7.1/demoapp.jar ./demoapp.jar
+
+USER app
+EXPOSE 8080
+
+ENV PORT=8080
+ENV JAVA_OPTS="-XX:MaxRAMPercentage=75.0 -XX:+UseContainerSupport -XX:+ExitOnOutOfMemoryError"
+
+ENTRYPOINT ["sh", "-c", "exec java $JAVA_OPTS -jar demoapp.jar"]