Simplify Drone CI by removing Gradle cache and redundant settings

.drone.yml

@@ -2,22 +2,15 @@ kind: pipeline
 type: docker
 name: ci
 
-# Enable BuildKit globally (docker plugin will pick this up)
 environment:
   DOCKER_BUILDKIT: 1
 
 steps:
   - name: test-and-jar
     image: gradle:8.10.2-jdk21
-    environment:
-      # Put the Gradle cache on a mounted volume
-      GRADLE_USER_HOME: /drone/.gradle
-    volumes:
-      - name: gradle-cache
-        path: /drone/.gradle
+    # No host volumes; keep cache in the container layer only
     commands:
       - gradle --version
-      # Single invocation -> one dependency resolution, better cache reuse
       - gradle --no-daemon clean test bootJar
 
   - name: build-image
@@ -30,22 +23,15 @@ steps:
         from_secret: docker_username
       password:
         from_secret: docker_password
-      # Keep your tags as-is
       tags:
         - ${DRONE_BRANCH/\//-}-${DRONE_COMMIT_SHA:0:7}
         - latest
-      # Enable BuildKit and add traceability labels (OCI standard)
       buildkit: true
       labels:
         org.opencontainers.image.source: ${DRONE_GIT_HTTP_URL}
         org.opencontainers.image.revision: ${DRONE_COMMIT_SHA}
         org.opencontainers.image.created: ${DRONE_BUILD_FINISHED}
         org.opencontainers.image.version: ${DRONE_TAG:-${DRONE_COMMIT_SHA:0:7}}
-    when:
-      branch:
-        include: [ main, develop ]
-      event:
-        include: [ push, pull_request, tag ]
 
   - name: publish-tag
     image: plugins/docker
@@ -57,7 +43,6 @@ steps:
         from_secret: docker_username
       password:
         from_secret: docker_password
-      # Tag builds get a clean semver tag
       tags:
         - ${DRONE_TAG}
       buildkit: true
@@ -66,18 +51,9 @@ steps:
         org.opencontainers.image.revision: ${DRONE_COMMIT_SHA}
         org.opencontainers.image.created: ${DRONE_BUILD_FINISHED}
         org.opencontainers.image.version: ${DRONE_TAG}
-    when:
-      event:
-        include: [ tag ]
 
 trigger:
   event:
     - push
     - pull_request
     - tag
-
-volumes:
-  # Host (or tmp) volume to persist Gradle cache between builds
-  - name: gradle-cache
-    host:
-      path: /tmp/drone/gradle-cache