perf(ci): reuse Git workspaces across builds

Jenkinsfile

@@ -152,11 +152,6 @@ pipeline {
                     }
                 }
             }
-            post {
-                always {
-                    cleanWs(deleteDirs: true, notFailBuild: true)
-                }
-            }
         }
 
         stage('生产环境部署确认（仅 production 执行）') {

Jenkinsfile.service

@@ -191,11 +191,6 @@ pipeline {
                     }
                 }
             }
-            post {
-                always {
-                    cleanWs(deleteDirs: true, notFailBuild: true)
-                }
-            }
         }
 
         stage('部署单个服务') {

scripts/controller-pipeline-contract.test.mjs

@@ -10,7 +10,7 @@ test('coordinator releases its builder while waiting for downstream jobs', () =>
   assert.match(pipeline, /stage\('确定构建范围'\) \{[\s\S]*?agent \{ label 'java-builder' \}/)
   assert.match(pipeline, /agent \{ label 'java-builder' \}/)
   assert.doesNotMatch(pipeline, /agent any/)
-  assert.doesNotMatch(pipeline, /post \{\s*always \{ cleanWs[\s\S]*?\}\s*\}\s*\}\s*$/)
+  assert.doesNotMatch(pipeline, /cleanWs\(/)
 })
 
 test('AUTO detects database migrations without expanding them to all services', () => {

scripts/test-environment-pipeline-contract.test.mjs

@@ -63,3 +63,9 @@ test('Java service images use the internal registry base image by default', () =
   assert.doesNotMatch(pipeline, /docker\.m\.daocloud\.io\/library\/eclipse-temurin/)
   assert.doesNotMatch(serviceDockerfile, /docker\.m\.daocloud\.io\/library\/eclipse-temurin/)
 })
+
+test('source workspaces are preserved for incremental Git fetches', () => {
+  assert.match(pipeline, /checkout scm/)
+  assert.equal((pipeline.match(/cleanWs\(/g) ?? []).length, 2)
+  assert.doesNotMatch(coordinatorPipeline, /cleanWs\(/)
+})