major improvements

scripts/build-desktop.bat

@@ -0,0 +1,32 @@
+@echo off
+setlocal
+set "SCRIPT_DIR=%~dp0"
+for %%I in ("%SCRIPT_DIR%..") do set "ROOT=%%~fI\"
+
+echo === Building Overlord Desktop (Tauri) ===
+pushd "%ROOT%Overlord-Desktop"
+
+where bun >nul 2>&1
+if errorlevel 1 (
+  echo error: bun is required ^(https://bun.sh^)
+  goto :err
+)
+where cargo >nul 2>&1
+if errorlevel 1 (
+  echo error: rust toolchain is required ^(https://rustup.rs^)
+  goto :err
+)
+
+call bun install || goto :err
+call bun run vendor || goto :err
+call bun run build:win || goto :err
+echo === Done — bundle output: Overlord-Desktop\src-tauri\target\release\bundle\ ===
+popd
+pause
+endlocal
+exit /b 0
+
+:err
+popd >nul 2>&1
+endlocal
+exit /b 1