build.ps1 移至 scripts/，路径基准改为仓库根目录

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

scripts/build.ps1

@@ -0,0 +1,12 @@
+# 编译脚本（位于 scripts/）：源码在 src/go/，产物输出到 build/relay.exe
+$ErrorActionPreference = 'Stop'
+$root = Split-Path $PSScriptRoot -Parent  # 仓库根目录（scripts/ 的上一级）
+$out  = Join-Path $root 'build\relay.exe'
+
+Push-Location (Join-Path $root 'src\go')
+try {
+    go build -o $out .
+    Write-Host "Built: $out"
+} finally {
+    Pop-Location
+}