Harden auth flows and add backend quality gate

scripts/build_release.ps1

@@ -3,6 +3,11 @@ $ErrorActionPreference = "Stop"
 $repoRoot = Resolve-Path "$PSScriptRoot\\.."
 Set-Location $repoRoot
 
+powershell -ExecutionPolicy Bypass -File (Join-Path $repoRoot "scripts\run_backend_quality_gate.ps1")
+if ($LASTEXITCODE -ne 0) {
+    throw "scripts/run_backend_quality_gate.ps1 failed with exit code $LASTEXITCODE."
+}
+
 $now = Get-Date
 $buildNumber = "{0}{1}{2}{3}{4}" -f $now.ToString("dd"), $now.ToString("MM"), $now.ToString("yy"), $now.ToString("HH"), $now.ToString("mm")