fix: restore "don't show again", and put Sharing in the drawer

[SiteRelEnby]

Two bugs found in 1.4.0 before it went to Play. 1.4.0 is already tagged and its GitHub release is published with signed open APKs, so these want a 1.4.1 rather than a re-cut: anyone who has installed sheaf-1.4.0-open.apk holds versionCode 104000, and re-issuing different bytes under that same code leaves them with no upgrade path.

"Don't show again" never survived a restart

ClientSettingsResponse names the field clientId; the server sends client_id; Moshi does not convert snake_case. Non-null with no default, so the missing field failed the whole response, and both callers wrap the call in runCatching - so every read of client settings threw, silently, for the life of the feature.

The write path was fine throughout. The dismissal reached the server and was stored; it just could never be read back, which is why this looked like a persistence bug rather than a parse one.

JsonDataException: Required value 'clientId' missing at $

A contract test now decodes the shape the server actually sends. It uses the app's own Moshi rather than a bare one, because this type is handled by KotlinJsonAdapterFactory and a plain builder cannot read it at all - which is also why the existing model tests never caught it.

I swept every model for the same mistake. The only other camelCase-without-@Json properties are on FrontUpdate, whose hand-written adapter writes the snake_case names itself, and on the watch's local-storage models, which never touch the wire.

Anything dismissed permanently before this stays dismissed - the data was always there.

Sharing was reachable only through Settings

It's where you go to take something down, which is not a thing to go hunting through Settings for, and web has had it as a top-level destination all along. It now joins the drawer with the rest of the system, and can be pinned to the bottom bar.

• The entry appears when the instance serves public profiles, or when it doesn't but this account still has grants on file. Grants outlive the instance switch, so hiding the entry in that case would leave somebody published with no way to reach the button that unpublishes them.
• Availability is re-asked whenever the drawer opens, so publishing a first link doesn't need a relaunch to reveal the entry.
• A pinned Sharing slot on a server that later turns sharing off keeps its place, dimmed, and says why when tapped, rather than disappearing from somebody's bar over a setting they don't control.
• The Settings > System row stays. A second way in costs nothing, and feat(settings): fold the Safety category into System #79 put it there deliberately.