Prepare Windows portable packaging

build-windows.ps1

@@ -0,0 +1,13 @@
+$ErrorActionPreference = "Stop"
+
+Write-Host "Creating or reusing the DataLoom Windows build environment..."
+if (-not (Test-Path ".venv\\Scripts\\python.exe")) {
+    py -3 -m venv .venv
+}
+
+& .venv\\Scripts\\python.exe -m pip install --upgrade pip
+& .venv\\Scripts\\python.exe -m pip install -e ".[build,test]"
+& .venv\\Scripts\\python.exe -m pytest -q
+& .venv\\Scripts\\python.exe -m PyInstaller --clean --noconfirm DataLoom.spec
+
+Write-Host "Portable executable created at dist\\DataLoom.exe"