Feed updates (Closes #344) (#356)

* Rework feed polling to correctly detect when new content is available (close #344)

* Tweak how the tuner works for consistency

* Improve the feed-update behavior after posting

* Load latest notifications when opening the tab

src/view/com/composer/Composer.tsx

@@ -166,7 +166,7 @@ export const ComposePost = observer(function ComposePost({
       setIsProcessing(false)
       return
     }
-    store.me.mainFeed.loadLatest()
+    store.me.mainFeed.checkForLatest({autoPrepend: true})
     onPost?.()
     hackfixOnClose()
     Toast.show(`Your ${replyTo ? 'reply' : 'post'} has been published`)