feat: split VFD backends by hardware

lib/led/detect.js

@@ -0,0 +1,22 @@
+'use strict';
+
+const fs = require('fs');
+
+function readDeviceModel() {
+  try {
+    return fs.readFileSync('/proc/device-tree/model', 'utf8')
+      .replace(/\0/g, '')
+      .trim();
+  } catch (_) {
+    return '';
+  }
+}
+
+function isRK3566() {
+  return /RK3566/i.test(readDeviceModel());
+}
+
+module.exports = {
+  readDeviceModel,
+  isRK3566,
+};