feat: 已有托盘在运行时，阻止托盘重复启动、且提供指引提示

[Antonoko]

#46

指引弹窗参考实现：

import ctypes

# 定义Windows API函数签名
MessageBox = ctypes.windll.user32.MessageBoxW

# 定义弹窗函数
def show_error_popup(message):
    MessageBox(None, message, "Windrecorder is already running", 0x40)

# 示例用法
show_error_popup("Another Windrecorder is running in system tray.\n\n已有「捕风记录仪」在系统托盘中运行。")