[Feature Request]: Add three missing App View queries — post search v2, external embed preview, and starter-pack membership

[KC-2001MS]

Summary

Three independent App View additions are present in upstream but missing from ATProtoKit. Each is a stable, single-endpoint sibling of an already-wrapped surface, so the additions are mechanical follow-ups rather than design decisions.

Pain points

• app.bsky.embed.getEmbedExternalView has no typed wrapper in ATProtoKit, so it cannot be called without dropping to raw XRPC.
• app.bsky.feed.searchPostsV2 is the v2 successor to searchPosts (already wrapped). Consumers cannot migrate without re-implementing the wrapper from scratch.
• app.bsky.graph.getStarterPacksWithMembership is the Starter Pack counterpart to the already-wrapped getListsWithMembership. Profile UIs cannot show "which Starter Packs contain this user" without dropping to raw XRPC.

Considered Alternatives

Raw XRPC per call site — works but each consumer reimplements the same wrapper shape.

Is this a breaking change?

No

Library Examples

N/A

Additional Context

Missing lexicons

Lexicon	Suggested wrapper
app.bsky.embed.getEmbedExternalView	getEmbedExternalView(url:)
app.bsky.feed.searchPostsV2	searchPostsV2(matching:limit:cursor:...)
app.bsky.graph.getStarterPacksWithMembership	getStarterPacksWithMembership(actor:limit:cursor:)

References

• getEmbedExternalView: https://github.com/bluesky-social/atproto/blob/main/lexicons/app/bsky/embed/getEmbedExternalView.json
• searchPostsV2: https://github.com/bluesky-social/atproto/blob/main/lexicons/app/bsky/feed/searchPostsV2.json
• getStarterPacksWithMembership: https://github.com/bluesky-social/atproto/blob/main/lexicons/app/bsky/graph/getStarterPacksWithMembership.json

[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.