Add JaCoCo for test coverage and update Drone CI settings

Integrate JaCoCo to enforce and report test coverage with a minimum threshold of 65%. Update Drone CI configuration to use a new Docker registry (rubble.se:5000) and add support for authentication with secrets.

.drone.yml

@@ -16,12 +16,16 @@ steps:
   - name: build-image
     image: plugins/docker
     settings:
-      registry: registry.local:5000
-      repo: registry.local:5000/hemhub/api
+      registry: rubble.se:5000
+      repo: rubble.se:5000/hemhub/api
       tags:
         - ${DRONE_BRANCH/\//-}-${DRONE_COMMIT_SHA:0:7}
         - latest
       dockerfile: Dockerfile
+      username:
+        from_secret: docker_username
+      password:
+        from_secret: docker_password
     when:
       branch:
         include: [ main, develop ]
@@ -31,11 +35,15 @@ steps:
   - name: publish-tag
     image: plugins/docker
     settings:
-      registry: registry.local:5000
-      repo: registry.local:5000/hemhub/api
+      registry: rubble.se:5000
+      repo: rubble.se:5000/hemhub/api
       tags:
         - ${DRONE_TAG}
       dockerfile: Dockerfile
+      username:
+        from_secret: docker_username
+      password:
+        from_secret: docker_password
     when:
       event:
         include: [ tag ]

build.gradle

@@ -2,6 +2,7 @@ plugins {
     id 'java'
     id 'org.springframework.boot' version '3.3.4'
     id 'io.spring.dependency-management' version '1.1.6'
+    id 'jacoco'
 }
 
 group = 'se.urmo'
@@ -21,4 +22,31 @@ dependencies {
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }
 
+test {
+    useJUnitPlatform()
+    finalizedBy jacocoTestReport
+}
+
+jacocoTestReport {
+    dependsOn test
+    reports {
+        xml.required = true
+        html.required = true
+    }
+}
+
+jacocoTestCoverageVerification {
+    violationRules {
+        rule {
+            limit {
+                counter = 'LINE'
+                value = 'COVEREDRATIO'
+                minimum = 0.65 // börja rimligt (65%), höj senare
+            }
+        }
+    }
+}
+
+check.dependsOn jacocoTestCoverageVerification
+
 tasks.test { useJUnitPlatform() }