Shadow refactoring and improvements (#1959)

* Make shadow a type-only concept

* Prevent unnecessary init state recalc

* Use derived state instead of effects

* Batch emitter updates

* Use object first seen time instead of dataUpdatedAt

* Stop threading dataUpdatedAt through

* Use same value consistently

src/view/com/lists/ListMembers.tsx

@@ -64,7 +64,6 @@ export function ListMembers({
 
   const {
     data,
-    dataUpdatedAt,
     isFetching,
     isFetched,
     isError,
@@ -185,7 +184,6 @@ export function ListMembers({
             (item as AppBskyGraphDefs.ListItemView).subject.handle
           }`}
           profile={(item as AppBskyGraphDefs.ListItemView).subject}
-          dataUpdatedAt={dataUpdatedAt}
           renderButton={renderMemberButton}
           style={{paddingHorizontal: isMobile ? 8 : 14, paddingVertical: 4}}
         />
@@ -198,7 +196,6 @@ export function ListMembers({
       onPressTryAgain,
       onPressRetryLoadMore,
       isMobile,
-      dataUpdatedAt,
     ],
   )