feat(members): set a member's emoji, and show it beside their name

[SiteRelEnby]

The phone could read a member's emoji but never write one, and only ever showed it as a stand-in avatar.

Two consequences: anyone who set both an emoji and an avatar picture never saw the emoji at all, since the picture replaced the only place it appeared. And there was no way to set one on Android in the first place - MemberCreate and MemberUpdate didn't carry the field, despite the server accepting it on both for a long time.

Setting it

An Emoji field in the member editor, next to Display Name, mirroring web's small emoji input.

Capped at the server's limit of 8, counted in code points rather than chars. A single emoji is often several UTF-16 units and a family sequence is seven, so a String.length cap would reject perfectly ordinary input while claiming a limit of 8.

Clearing sends an empty string, not null. The member PATCH is omit-means-unchanged and Moshi drops nulls, so a null would silently leave the old emoji in place - the field would be settable but never unsettable. That's the same trap as #68 in this batch, and the scratchpad note field already solves it the same way.

Showing it

Now matches web and the watch: the emoji sits in front of the name in the members list, the profile title, the fronting cards on Home, the switch sheet, the quick-switch chips, history rows, and the member rows inside a group.

displayNameWithEmoji is deliberately display-only. Sorting, searching and content descriptions keep displayNameOrName, because a prefix there would file the whole roster under one character, stop a name query matching, and make a screen reader announce an emoji before every name. Of the 62 places a member's name is rendered, nine are actual name displays; a diff check confirms no sort or search site changed.

Testing

:app:assemblePlayRelease, :app:assembleOpenRelease, :app:testPlayReleaseUnitTest green. Unit tests cover the emoji reaching the wire on create and update, the empty-string clear, the display property with and without an emoji, and that the plain name and initials stay emoji-free.

Device checklist:

• Set an emoji on a member, save: it appears before their name in the list and on their profile
• A member with an emoji and an avatar picture: avatar shows the picture, name still shows the emoji
• A member with an emoji and no picture: the emoji stands in for the avatar, as before
• Clear the emoji and save: it goes, and stays gone after reopening
• Paste a long string of emoji: input stops at 8, save succeeds with no error
• Paste a family emoji: accepted, not rejected as too long
• Search for a member by name: still matches, and the roster is still sorted by name not emoji
• Check Home, the switch sheet, quick-switch chips, history and a group's member list