Add Translation and Slow Mode docs code samples

[martinmitrevski]

Requested in GetStream/docs-content#1497 — keeping docs snippets compiled here so the SDK and docs stay in sync.

Two new files alongside the existing *CodeSamples.cs:

File	Backs
TranslationCodeSamples.cs	Translation
SlowModeCodeSamples.cs	Slow Mode & Throttling

Why these two

Both docs pages carried a // This feature is not yet available in the Unity SDK placeholder for every Unity tab, but the client-side APIs already ship:

• Translation — IStreamMessage.I18n exposes the translation dictionary, IStreamChannel.AutoTranslationEnabled / AutoTranslationLanguage expose the channel settings, and StreamUserUpsertRequest.Language sets a user's language. Only the translate endpoint and app-level auto-translation are genuinely server-side, and the sample says so in a comment.
• Slow Mode — there's no dedicated method, but channel.UpdatePartialAsync sets the cooldown field and IStreamChannel.Cooldown reads it back. The second sample computes the remaining cooldown from Cooldown plus the local user's last message, since the SDK doesn't track that for you — this is the part a Unity app needs in order to gate its send button.

Notes for review

• Both follow the conventions in this folder: internal sealed class, private IStreamChatClient Client { get; } = StreamChatClient.CreateDefaultClient();, and doc-extracted regions dedented to column 0.
• SlowModeCodeSamples.GetRemainingCooldown is the one piece of real logic rather than an API call. It's deliberately framed as "here's how you'd compute this" — if you'd prefer a GetRemainingCooldown() helper on IStreamChannel instead, that would make both the sample and the docs page a couple of lines long, and I'd happily follow up.
• I haven't been able to open this in the Editor, so the samples are unverified against an actual compile — every symbol and signature was checked against develop, but a build on your side would be worth having before merge.

🤖 Generated with Claude Code

[sierpinskid]

best to provide full online URL (like on other examples) so we can easily jump to page from

[martinmitrevski]

Done in 536d9dd — switched to the ClientAndUsersCodeSamples.cs convention: a per-method <summary> with the full ?language=unity URL and a section anchor, rather than one class-level comment.

• ReadMessageTranslations → .../translation/?language=unity#i18n-data
• EnableChannelAutoTranslation → .../translation/?language=unity#enabling-automatic-translation
• SetUserLanguage → .../translation/?language=unity#set-user-language
• EnableDisableSlowMode, GateSendingUiOnRemainingCooldown → .../slow-mode/?language=unity#channel-slow-mode

Both pages return 200 and I checked the anchor ids against the rendered HTML, so all five links land on the right section. Both slow mode samples point at the same anchor because that page has no subheading for the remaining-cooldown part — worth splitting on the docs side later.