Fix Gradle daemon not being reused (#24)

Dockerfile

@@ -3,12 +3,10 @@
 # (using this Gradle Wrapper version) remains aligned with the production Dockerfile (using vanilla Gradle)
 FROM gradle:8.7-alpine AS build
 
-RUN ["gradle", "init"]
 COPY ./app /app
-
 WORKDIR /app
 
-RUN ["gradle", "jar"]
+RUN gradle init && gradle :jar
 
 FROM azul/zulu-openjdk-alpine:21-latest
 
@@ -18,7 +16,6 @@ ENV UPDATE_WINDOW_SECONDS="45"
 ENV LOG_LEVEL="INFO"
 
 WORKDIR /app
-
 COPY --from=build /app/build/libs/*.jar app.jar
 
 ENTRYPOINT ["java", "-jar", "app.jar"]