fix(java-client): checkGeneratedClean via ProviderFactory.exec — Project.exec is gone in Gradle 9

clients/java/zb-mom-ww-mxgateway-client/build.gradle

@@ -72,16 +72,18 @@ tasks.register('checkGeneratedClean') {
     group = 'verification'
     description = 'Fails if the committed generated Java tree differs from a fresh regeneration.'
     dependsOn 'generateProto'
+    def generatedDir = 'clients/java/src/main/generated'
+    def repoRoot = rootProject.projectDir.parentFile.parentFile
+    // Project.exec was removed in Gradle 9; ProviderFactory.exec runs the git-status probe
+    // lazily (captured at configuration time, evaluated in doLast) and works on both the
+    // installed Gradle and Gradle 9.
+    def gitStatus = providers.exec {
+        workingDir(repoRoot)
+        commandLine('git', 'status', '--porcelain', '--', generatedDir)
+        ignoreExitValue = true
+    }
     doLast {
-        def generatedDir = 'clients/java/src/main/generated'
-        def stdout = new ByteArrayOutputStream()
-        def result = exec {
-            workingDir = rootProject.projectDir.parentFile.parentFile
-            commandLine 'git', 'status', '--porcelain', '--', generatedDir
-            standardOutput = stdout
-            ignoreExitValue = true
-        }
-        def dirty = stdout.toString().trim()
+        def dirty = gitStatus.standardOutput.asText.get().trim()
         if (!dirty.isEmpty()) {
             throw new GradleException(
                 "Generated Java is stale:\n${dirty}\n" +