Modernize invertergui: MQTT write support, HA integration, UI updates

vendor/github.com/prometheus/procfs/internal/util/parse.go

@@ -1,4 +1,4 @@
-// Copyright 2018 The Prometheus Authors
+// Copyright The Prometheus Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
@@ -14,6 +14,7 @@
 package util
 
 import (
+	"errors"
 	"os"
 	"strconv"
 	"strings"
@@ -110,3 +111,16 @@ func ParseBool(b string) *bool {
 	}
 	return &truth
 }
+
+// ReadHexFromFile reads a file and attempts to parse a uint64 from a hexadecimal format 0xXX.
+func ReadHexFromFile(path string) (uint64, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	hexString := strings.TrimSpace(string(data))
+	if !strings.HasPrefix(hexString, "0x") {
+		return 0, errors.New("invalid format: hex string does not start with '0x'")
+	}
+	return strconv.ParseUint(hexString[2:], 16, 64)
+}