完善后端联调链路与模拟器多通道支持

backend/start-backend.ps1

@@ -0,0 +1,13 @@
+Set-StrictMode -Version Latest
+$ErrorActionPreference = "Stop"
+
+$backendDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+$scriptPath = Join-Path $backendDir "scripts\start-dev.ps1"
+
+if (-not (Test-Path $scriptPath)) {
+  throw ("Backend start script not found: " + $scriptPath)
+}
+
+Set-Location $backendDir
+
+powershell -ExecutionPolicy Bypass -File $scriptPath