feat(electron): separate dev/uat build targets with isolated update channels

- Add build.dev.json to override publish.url for dev environment
- Add build:dev and build:uat scripts; each sets its own feed URL
- copy-to-nas.js now accepts env argument; outputs to
  electron-update/{dev|uat}/ locally and on NAS
- docker-compose volume mounts updated to serve from env subdirs
- Remove stale artifacts from electron-update root

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

electron/scripts/copy-to-nas.js

@@ -1,11 +1,12 @@
 const fs = require('fs')
 const path = require('path')
 
+const env = process.argv[2] || 'uat'
 const srcDir = path.join(__dirname, '..', 'dist')
-// 项目根目录下的 electron-update，用于 docker volume 挂载给 nginx
-const localUpdateDir = path.join(__dirname, '..', '..', 'electron-update')
+// 项目根目录下的 electron-update/{env}，用于 docker volume 挂载给 nginx
+const localUpdateDir = path.join(__dirname, '..', '..', 'electron-update', env)
 // NAS 共享路径
-const nasDir = '\\\\JIULUGNAS\\personal_folder\\CodeSpace\\GameGroup2\\electron-update'
+const nasDir = path.join('\\\\JIULUGNAS\\personal_folder\\CodeSpace\\GameGroup2\\electron-update', env)
 
 function ensureDir(dir) {
   try {
@@ -26,7 +27,6 @@ function copyFilesTo(destDir, label) {
   }
 
   const files = fs.readdirSync(srcDir).filter((f) => {
-    // 只复制更新相关文件：安装包、yml、blockmap、nupkg
     const ext = path.extname(f).toLowerCase()
     return (
       ext === '.exe' ||