fix jenkins checkout: skip default full checkout, use shallow clone

platform/Jenkinsfile

@@ -7,10 +7,25 @@ pipeline {
         }
     }
 
+    options {
+        skipDefaultCheckout()
+    }
+
     stages {
         stage('Checkout') {
             steps {
-                echo '✅ Code checked out from gitea'
+                checkout([
+                    $class: 'GitSCM',
+                    branches: scm.branches,
+                    userRemoteConfigs: scm.userRemoteConfigs,
+                    extensions: [[
+                        $class: 'CloneOption',
+                        shallow: true,
+                        depth: 1,
+                        noTags: true,
+                        timeout: 20
+                    ]]
+                ])
             }
         }