fixup! wip: ci: Begin Jenkins pipeline

ci/Jenkinsfile

@@ -33,6 +33,15 @@ pipeline {
                 sh 'git clean -fdx'
             }
         }
+
+        stage('Prepare') {
+            steps {
+                container('jnlp') {
+                    sh 'git submodule update --remote aimee-os'
+                }
+            }
+        }
+
         stage('Build') {
             steps {
                 sh 'make config && make update-config'
@@ -41,10 +50,12 @@ pipeline {
             post {
                 success {
                     dir('_build/images') {
+                        sh 'zstd firmware.img'
+                        sh 'zstd sdcard.img'
                         archiveArtifacts([
-                            'firmware.img',
+                            'firmware.img.zst',
                             'rootfs.squashfs',
-                            'sdcard.img',
+                            'sdcard.img.zst',
                         ].join(','))
                     }
                 }