Fix orphaned feed slices, handle blocks (#4944)

* Fix orphaned feed slices, handle blocks

* Revert to filerting out orphan threads

* Support NotFoundPost views too

* Just kidding, use ReplyRef.root as source of grandparent data

* Fixes

src/state/queries/post-feed.ts

@@ -80,6 +80,7 @@ export interface FeedPostSliceItem {
   moderation: ModerationDecision
   parentAuthor?: AppBskyActorDefs.ProfileViewBasic
   isParentBlocked?: boolean
+  isParentNotFound?: boolean
 }
 
 export interface FeedPostSlice {
@@ -326,6 +327,7 @@ export function usePostFeedQuery(
                         moderation: moderations[i],
                         parentAuthor: item.parentAuthor,
                         isParentBlocked: item.isParentBlocked,
+                        isParentNotFound: item.isParentNotFound,
                       }
                       return feedPostSliceItem
                     }),