Integrate syntax sugar for repo operations upon records

[MarshalX]

i dont like it so bad how it works with response models...

[MarshalX]

why not place these models directly right after the record model itself?

• 1 shared model for sync and async
• models stay in the "models" module only
• shortcuts to models will work great with it

instead of async_ns.PostRecord.CreateRecordResponse we will have typical models import as we had before: models.AppBskyFeedPost.CreateRecordResponse. and the record itself is models.AppBskyFeedPost.Record