Remove (?) mostly-redundant recipient headers in DM narrow

[chrisbobbe]

Much like an issue for topic narrows:

• Fuse recipient header into app bar for topic narrows #1039

but this is for DM narrows. Currently it looks like this:

Many messages	Few messages

We have a design from Vlad showing the many-messages case:

https://www.figma.com/design/1JTNtYo9memgW7vV6d0ygq/Zulip-Mobile?node-id=4933-16071&m=dev

which looks like it just removes the recipient headers. Perhaps we should do that, but first let's consider some design questions Greg raised for topic narrows in #1039 (comment) which seem equally relevant to DM narrows:

Design questions we'll want to resolve before implementing this include:

• Have an example where the thread is shorter than the screen, so there's empty space between the app bar and the first message; make sure we're happy with how that looks, or adjust something. (Possibly switch to pinning the earliest message at the top instead of the latest at the bottom, so the empty space goes between the last message and the compose box.)
• Decide how to handle showing the messages' dates, which currently live in the recipient header.

cc @terpimost for those design questions.

[chrisbobbe]

Milestoning M7: Future to match #1039.

[alya]

Related discussion

[terpimost]

example where the thread is shorter than the screen

I updated Figma with this example:

I thought that messages are just stick to top unless they are longer than available screen + some gutter (min 8px) and then just scroll.

Decide how to handle showing the messages' dates

We discussed that with @gnprice and thought that consequent messages date and times are not that important to have always be displayable, so decision is to show them in the context menu, where we see message preview with an author always:

Figma area about this

[gnprice]

Thanks for the update!

I think the second part of your comment is about #457, or an alternative that we'll do instead of #457. But my second question was about the dates, not the times. I don't see a date in your second screenshot.

[terpimost]

Oh, sorry. Do you guys talk about this case?

And there is nothing above...