Register a new TokenPay payment plugin with configurable API
credentials, payment URL generation, and signed callback
verification.
Also improve admin config fetching to support single-group
lookups and add backwards-compatible subscribe template loading
from legacy settings and bundled files when the database table
is unavailable.
- Add command support for plugin management
- Optimize plugin management page layout
- Add email copy functionality for users
- Convert payment methods and Telegram Bot to plugin system
yinjianm