新增讨论功能

新增站内信功能

新增安装向导功能

修正时间显示问题

修复PayPal回调报错问题

安全相关：修复了贝宝（PayPal）支付绕过漏洞；仅在扣款确认成功后才授予对应内容。感谢 kta1kri。

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Added discussion feature

Added internal message feature

Added installation wizard

Fixed time display issue

Fixed PayPal callback error

Security: Fixed PayPal payment bypass; content is granted only after a confirmed capture. Thanks to kta1kri(https://github.com/kta1kri).