Sync notifications between Trac and GitHub

[cooljeanius]

See this downstream ticket I opened on the MacPorts Trac: https://trac.macports.org/ticket/68357
Basically, when a project has a presence on both Trac and GitHub, sometimes people will miss things on one place because they only check their notifications on one of the two places. Syncing notifications would help keep people up-to-date about things they may have missed on the other end of the bridge.
(N.B. I'm not sure if this is actually possible; if it isn't, feel free to close)

[neverpanic]

GitHub only supports access to notifications when authenticating with a personal access token.

From https://docs.github.com/en/rest/activity/notifications?apiVersion=2022-11-28#about-github-notifications:

These endpoints only support authentication using a personal access token (classic).

Since trac-github does not use personal access tokens, this would require asking users to provide a personal access token, and storing those tokens in the trac database on behalf of the user. This would be pretty bad user experience, and it would only work for the few users that actually opt into this.

Personally, I don't think that's a good balance in the risk & effort vs. reward calculation; the OAuth2 tokens that trac-github currently handles either don't have any permissions, or are able to read all email addresses, and that's it. The effort required to get this implemented for the few users that would provide an access token is also not worth it, IMHO.

[cooljeanius]

OK yeah, that's probably more complicated than necessary; darn...
(my related request, MacPorts Trac 68357, still stands, though)