Add support for manual retry of downloading attachments

[hseg]

Came up when testing #191 -- once nchat has given up on an attachment, it is marked as unavailable, even if the error was on the client end. Either be smarter about this, or just give a mechanism to force-retry downloading.

[d99kris]

Thanks for suggesting an improvement. Can I confirm you're using WhatsApp?
For Telegram there's a manual way (deleting cache files in the filesystem) to clear attachment cache state, but no such way in WhatsApp currently.

[hseg]

On Fri, Mar 01, 2024 at 05:34:56AM -0800, Kristofer Berggren wrote: Thanks for suggesting an improvement. Can I confirm you're using WhatsApp? For Telegram there's a manual way (deleting cache files in the filesystem) to clear attachment cache state, but no such way in WhatsApp currently.

Yes, I'm using Whatsapp, sorry for not specifying.

[d99kris]

No worries, thanks for confirming 👍