feat(ci): add version linter

Makefile

@@ -6,6 +6,7 @@ fmt:
 
 lint:
 	@./gradlew pmdMain
+	@./gradlew lintProjectVersion
 
 test:
 	@./gradlew test

build.gradle

@@ -113,6 +113,8 @@ subprojects {
 			logger.warn("VERSION file not found in project '${project.path}'. Skipping version setting.")
 		}
 
+		tasks.register('lintProjectVersion', VersionCheckTask) {}
+
 		java {
 			withSourcesJar()
 			withJavadocJar()

buildSrc/src/main/groovy/VersionCheckTask.groovy

@@ -0,0 +1,24 @@
+import org.gradle.api.DefaultTask
+import org.gradle.api.tasks.TaskAction
+import org.gradle.api.tasks.Input
+import org.gradle.api.GradleException
+
+class VersionCheckTask extends DefaultTask {
+    @Input
+    def versionRegex = ~/^[0-1]\.\d+\.\d+$/
+
+    @TaskAction
+    def checkVersion() {
+        File versionFile = project.file('VERSION')
+
+        if (!versionFile.exists()) {
+            logger.quiet("VERSION file not found in subproject: ${project.name}")
+            return
+        }
+
+        def version = versionFile.text.trim()
+        if (!(version =~ versionRegex)) {
+            throw new GradleException("Version '${version}' in project '${project.name}' does not match regex: ${versionRegex}")
+        }
+    }
+}