Support for Subdomains in HidyBot

By adding a subdomain, that domain can be used to display user subscriptions. If multiple domains are added, a list of domains will be shown to the user, allowing them to select their preferred domain and receive a subscription link tailored to that domain.

Now, it's possible to add multiple subdomains to each server.

If no domains are added, subscription links will be generated from the server's main domain.

This feature allows users to create custom subscription links based on various domains according to their preferences.