feat(deploy): initialize authentication security secrets

update.ps1

@@ -172,6 +172,11 @@ if (-not $skipRepoUpdate) {
     Write-Host ""
 }
 
+# 空值或历史默认值只初始化一次并写回 .env；已有自定义值及数据库轮转配置不受影响。
+if (-not (Test-Path ".env")) { Write-Err "未找到 .env，请先执行 start.ps1 完成初始化" }
+. (Join-Path $scriptDir "scripts\Initialize-SecurityEnv.ps1")
+Initialize-SecurityEnv -Path (Join-Path $scriptDir ".env") -Mode "upgrade"
+
 # ==================== Docker 检查 ====================
 function Test-DockerInstalled {
     $docker = Get-Command docker -ErrorAction SilentlyContinue