fix(jenkins): SNAPSHOT 模式自动递增 alpha 版本号（查询 registry 最新 alpha 后 +1）

Jenkinsfile

@@ -91,8 +91,23 @@ pipeline {
 
                         def newVer
                         if (params.SNAPSHOT) {
-                            // SNAPSHOT：仅追加 -alpha.1 后缀，不修改 package.json，不 commit
-                            newVer = baseVer + '-alpha.1'
+                            // SNAPSHOT：查询 registry 上最新的 alpha 版本，自动递增
+                            def alphaNum = 1
+                            try {
+                                def remoteVer = bat(
+                                    script: "@npm view ${pkg} dist-tags.alpha --registry %NEXUS_REGISTRY% 2>nul",
+                                    returnStdout: true
+                                ).trim()
+                                if (remoteVer && remoteVer.matches(/.*-alpha\.\d+$/)) {
+                                    def matcher = (remoteVer =~ /-alpha\.(\d+)$/)
+                                    if (matcher.find()) {
+                                        alphaNum = matcher.group(1).toInteger() + 1
+                                    }
+                                }
+                            } catch (Exception e) {
+                                echo "Could not query remote version for ${pkg}, using alpha.1"
+                            }
+                            newVer = baseVer + "-alpha.${alphaNum}"
                             echo "SNAPSHOT publish: ${pkg} → ${newVer} (tag: alpha)"
                             // 临时写入 package.json 供 npm publish 读取（不 commit）
                             bat """node -e "var fs=require('fs'),p='${dir}/package.json',j=JSON.parse(fs.readFileSync(p,'utf8'));j.version='${newVer}';fs.writeFileSync(p,JSON.stringify(j,null,2)+'\\n','utf8');" """