way to look up PM ID

[33mhz]

The way PMs are handled, I can't look up the ID of a PM between me and other people unless I know the ID of the channel (if it exists). If it's not in the first 20 (or first 200) channels I'm subscribed to, or something similar, it can be hard to find out if a channel exists already. It would be convenient to be able to look that up.

Submit a list of user_ids/@-usernames and return the existing PM channel_id if it exists.

[33mhz]

URL like so: https://api.pnut.io/v0/users/me/channels/existing_pm?ids=1,4,@33mhz,53

Will return the channel if it exists, or a 404 otherwise. Returns 404 if one of the users is blocked.

[33mhz]

Implemented.