Topic action sheet can be hard to discover

[gnprice]

If you long-press a message, we show you a bottom sheet with actions you can take on the message: react, star, mark unread, etc. If you long-press a topic (in the inbox, or a recipient header, or an app bar), we show you a bottom sheet with actions you can take on the topic: mute, follow, etc.

(In main we don't yet actually have a topic action sheet; but we do in today's preview beta v0.0.23, with #1041, and will soon in main.)

The trouble with putting features behind a long-press is that that gesture can be a non-obvious thing to try. A beta user writes:

I would not have tried long-pressing the topic to find the option to follow it, if you'd not mentioned the feature must exist somewhere, and thus I started trying things; I feel like intuitively I was expecting it to be in the long-press actions menu for a message.

The flip side is that giving some piece of UI a long-press gesture doesn't add any visual clutter. That's the major reason we've relied on long-press gestures, in exactly the same ways, for offering these features in the zulip-mobile legacy app.

So for anything we might do to address this, we'll need to be mindful to avoid going down a road that makes the UI crowded all the time with widgets for Zulip's many features — that'd make things hard to discover and use too.

This issue will require UI design discussion in #mobile before it's ready for anything to be implemented.