fix(ci): 健壮化 Inno Setup 安装 + 部署仅保留最新安装包

- 新增 install-innosetup.ps1：校验下载大小、检查安装程序退出码、双
  Program Files 目录定位 ISCC，修复原内联命令静默成功但没真正装上的问题
  （SYSTEM 账户下 Invoke-WebRequest 无 -UseBasicParsing + 未检查退出码）
- provision/compile-windows.sh 在两个 Program Files 目录查找 ISCC
- deploy.sh 发布安装包到 /opt/jiu/downloads 前先清旧包，仅保留最新版本

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/ci/deploy.sh

@@ -131,8 +131,10 @@ mkdir -p /opt/jiu/marketing
 rsync -a --delete /tmp/jiu-marketing-new/ /opt/jiu/marketing/
 rm -rf /tmp/jiu-marketing-new
 
-# Publish desktop client installers to the nginx-served downloads dir
+# Publish desktop client installers to the nginx-served downloads dir.
+# Keep only the latest version: clear old installers, then drop in the new ones.
 mkdir -p /opt/jiu/downloads
+rm -f /opt/jiu/downloads/jiu-windows-* /opt/jiu/downloads/jiu-macos-* 2>/dev/null || true
 [ -f /tmp/jiu-windows-x64-setup.exe ] && mv -f /tmp/jiu-windows-x64-setup.exe /opt/jiu/downloads/ || true
 [ -f /tmp/jiu-macos-x64.zip ] && mv -f /tmp/jiu-macos-x64.zip /opt/jiu/downloads/ || true