fix: add Weixin.exe to Windows process name detection

[aviky-2]

Summary

Chinese version of WeChat (微信) uses Weixin.exe as the main process name, not WeChat.exe. This causes vchat setup to fail with "微信主进程没在运行" on Chinese Windows installations.

Fix

Changed find_keys_windows.py:94 from exact match to tuple match:

# Before
if entry.szExeFile.lower() == "wechat.exe":

# After  
if entry.szExeFile.lower() in ("wechat.exe", "weixin.exe"):

Verification

• vchat setup now correctly detects Weixin.exe on Chinese Windows
• Both WeChat.exe (international version) and Weixin.exe (Chinese version) are supported

Closes #2