docs: Refine README for pure Go engine and add SETUP_CERTS.cmd

SETUP_CERTS.cmd

@@ -0,0 +1,13 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+echo [SETUP] Installing Ananta local root CA certificate...
+certutil -addstore -f "Root" "certs\Ananta-local-root.cer"
+if errorlevel 1 (
+  echo [ERROR] Failed to install certificate. Please run as Administrator.
+  pause
+  exit /b 1
+)
+echo [OK] Root certificate installed successfully.
+pause
+exit /b 0