Added cross-OS win

hmi_gui/build_windows.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+# Ensure the Windows target is installed
+rustup target add x86_64-pc-windows-gnu
+
+# Check for mingw-w64
+if ! command -v x86_64-w64-mingw32-gcc &> /dev/null
+then
+    echo "Error: x86_64-w64-mingw32-gcc not found."
+    echo "Install it via your package manager (e.g., sudo apt install mingw-w64)"
+    exit 1
+fi
+
+# Build for Windows
+cargo build --release --target x86_64-pc-windows-gnu
+
+echo "-----------------------------------"
+echo "Build complete."
+echo "Windows binary: target/x86_64-pc-windows-gnu/release/esp32p4-waveform-gui.exe"