Support blocking and/or reporting a user from the Invite dialogue #2263
Description
Describe the problem
As discussed in previous issues (#1845, #2257), invite spam is a problem on Matrix in general. The ideal solution to this would be something proactive like #1845 or contextually disabling invites using matrix-org/matrix-spec-proposals#2666, but these solutions are complex and/or reliant upon future spec changes and will likely take considerable time to implement. During this time, users must continue to receive malicious invites and manually decline them individually.
A common spam practice is to spam a room where many users are located, then mass-invite them to offensively designated chats. Mods and/or bots can usually handle the room-side spam, but the invites remain an end-user problem. This becomes especially problematic in cases where Cinny user either does not know which room the spam invites originated from or the spam messages have already been removed, which leaves no GUI method of blocking the user and requires technical knowledge of slash commands to deal with.
Describe the solution you'd like
I don't have an invite up currently to describe the exact verbiage, but if I remember correctly, the chat invite screen has two options which effectively amount to "Accept" and "Decline". I propose that this be extended with two more options: Block User and Block and Report User.
The former (Block User) would add the inviting user to Cinny user's block list. Depending on how Cinny operates, this may already hide the other invites if it is part of invite-spam from the same user. If it doesn't do that automatically, I would suggest that it should. Whether that means refreshing the invite list when a new user is added to block list, automatic declining of all blocked-user requests, etc. is not particularly important from the end-user perspective, but all other invites from the blocked user should go away when the user is blocked, via any mechanism.
Block and Report User should do the same as the above but also open a report dialogue to report the user to their homeserver admins/abuse team/wherever reports go for that homeserver.
Alternatives considered
Waiting for a different solution is one alternative. However, the usefulness of being able to block persistent invites extends beyond spam. Not all persistent invites are necessarily from spammers, there are other bad actors (like Jared Leto) who may abuse invites to stalk and harass users or even potentially well-meaning but annoying users sending repeat invites.
I hold that this feature would be useful even in the event that more proactive invite abuse handling were added to Matrix and/or Cinny.
Additional context
No response