[Feature]: Set share domain

Feature Summary

Ability to set a different domain for sharing

What problem does this feature solve?

I am currently accessing miniflux via my local-only accessible domain. Because I use a local-only accessible domain, I am not able to share my feed articles to others.

I have a publically accessible domain that I could reverse proxy to the /share function of miniflux, but I need a way to set the domain so that miniflux will return the shared public URLs to me based on what I've set as the share domain.

Proposed Solution

e.g.

I access miniflux via https://localhost.test/miniflux.

I update miniflux settings to set my public/external domain to https://external.domain/feeds**.

and then I read and share an article publically and miniflux returns a url of:

https://external.domain/feeds/share/<share hash>

** Would be dope if we could change the basedir as well, but if it's tied to the internal basedir, that's fine too!

Alternatives Considered

No response

Additional Context

No response

Checklist

• I have searched existing issues to ensure this feature hasn't been requested before.
• I understand that feature requests are not guaranteed to be implemented.
• I agree to follow the project's contribution guidelines.