[Feature Request]: Add `chat.bsky.notification` preferences support

[KC-2001MS]

Summary

chat.bsky.notification.* (defs / getPreferences / putPreferences) is missing from ATProtoKit. The lexicon mirrors the existing app.bsky.notification.{getPreferences, putPreferences} shape exactly but on the api.bsky.chat host, so clients cannot expose typed access to DM notification toggles.

Pain points

No way to fetch or update the user's DM notification preferences through the typed pipeline; consumers must drop down to raw XRPC and re-implement api.bsky.chat routing.

Considered Alternatives

Raw XRPC for the chat notification preferences endpoint pair — loses typed pipeline and forces every consumer to repeat the host routing.

Is this a breaking change?

No

Library Examples

N/A

Additional Context

Missing lexicons

Lexicon	Suggested wrapper
chat.bsky.notification.defs	types only
chat.bsky.notification.getPreferences	getChatNotificationPreferences()
chat.bsky.notification.putPreferences	putChatNotificationPreferences(_:)

All sit on api.bsky.chat and require isRelatedToBskyChat: true routing.

References

• Lexicon root: https://github.com/bluesky-social/atproto/tree/main/lexicons/chat/bsky/notification
• Affected directory: Sources/ATProtoKit/Models/Lexicons/chat.bsky/Notification/ (new), Sources/ATProtoKit/APIReference/ChatBskyAPI/ (new method files)

[KC-2001MS]

As we discussed, I've filed the missing features as separate feature requests for tracking. None of them are urgent on my end, so I plan to follow up on each as the need actually arises.

Given that ATLexiconC is on the horizon, please feel free to handle these at your own pace — there's no rush, and it may well make sense to let ATLexiconC cover some of them rather than typing everything out by hand. I'm happy to help and provide corrections whenever it's useful.