New onboarding (#241)

* delete old onboarding files and code

* add custom FollowButton component to Post, FeedItem, & ProfileCard

* move building suggested feed into helper lib

* show suggested posts/feed if follower list is empty

* Update tsconfig.json

* add pagination to getting new onboarding

* remove unnecessary console log

* fix naming, add better null check for combinedCursor

* In locally-combined feeds, correctly produce an undefined cursor when out of data

* Minor refactors of the suggested posts lib functions

* Show 'follow button' style of post meta in certain conditions only

* Only show follow btn in posts on the main feed and the discovery feed

* Add a welcome notice to the home feed

* Tune the timing of when the welcome banner shows or hides

* Make the follow button an observer (closes #244)

* Update postmeta to keep the follow btn after press until next render

* A couple of fixes that ensure consistent welcome screen

* Fix lint

* Rework the welcome banner

* Fix cache invalidation of follows model on user switch

* Show welcome banner while loading

* Update the home onboarding feed to get top posts from hardcode recommends

* Drop unused helper function

* Update happy path tests

---------

Co-authored-by: Paul Frazee <pfrazee@gmail.com>

src/view/com/util/PostMeta.tsx

@@ -1,37 +1,74 @@
 import React from 'react'
-import {Platform, StyleSheet, View} from 'react-native'
+import {StyleSheet, View} from 'react-native'
 import {Text} from './text/Text'
 import {ago} from 'lib/strings/time'
 import {usePalette} from 'lib/hooks/usePalette'
+import {useStores} from 'state/index'
+import {observer} from 'mobx-react-lite'
+import FollowButton from '../profile/FollowButton'
 
 interface PostMetaOpts {
   authorHandle: string
   authorDisplayName: string | undefined
   timestamp: string
+  did: string
+  declarationCid: string
+  showFollowBtn?: boolean
 }
 
-export function PostMeta(opts: PostMetaOpts) {
+export const PostMeta = observer(function (opts: PostMetaOpts) {
   const pal = usePalette('default')
   let displayName = opts.authorDisplayName || opts.authorHandle
   let handle = opts.authorHandle
+  const store = useStores()
+  const isMe = opts.did === store.me.did
 
-  // HACK
-  // Android simply cannot handle the truncation case we need
-  // so we have to do it manually here
-  // -prf
-  if (Platform.OS === 'android') {
-    if (displayName.length + handle.length > 26) {
-      if (displayName.length > 26) {
-        displayName = displayName.slice(0, 23) + '...'
-      } else {
-        handle = handle.slice(0, 23 - displayName.length) + '...'
-        if (handle.endsWith('....')) {
-          handle = handle.slice(0, -4) + '...'
-        }
-      }
-    }
+  // NOTE we capture `isFollowing` via a memo so that follows
+  //      don't change this UI immediately, but rather upon future
+  //      renders
+  const isFollowing = React.useMemo(
+    () => store.me.follows.isFollowing(opts.did),
+    [opts.did, store.me.follows],
+  )
+
+  if (opts.showFollowBtn && !isMe && !isFollowing) {
+    // two-liner with follow button
+    return (
+      <View style={[styles.metaTwoLine]}>
+        <View>
+          <Text
+            type="lg-bold"
+            style={[pal.text]}
+            numberOfLines={1}
+            lineHeight={1.2}>
+            {displayName}{' '}
+            <Text
+              type="md"
+              style={[styles.metaItem, pal.textLight]}
+              lineHeight={1.2}>
+              &middot; {ago(opts.timestamp)}
+            </Text>
+          </Text>
+          <Text
+            type="md"
+            style={[styles.metaItem, pal.textLight]}
+            lineHeight={1.2}>
+            {handle ? (
+              <Text type="md" style={[pal.textLight]}>
+                @{handle}
+              </Text>
+            ) : undefined}
+          </Text>
+        </View>
+
+        <View>
+          <FollowButton did={opts.did} declarationCid={opts.declarationCid} />
+        </View>
+      </View>
+    )
   }
 
+  // one-liner
   return (
     <View style={styles.meta}>
       <View style={[styles.metaItem, styles.maxWidth]}>
@@ -53,13 +90,18 @@ export function PostMeta(opts: PostMetaOpts) {
       </Text>
     </View>
   )
-}
+})
 
 const styles = StyleSheet.create({
   meta: {
     flexDirection: 'row',
     alignItems: 'baseline',
-    paddingTop: 0,
+    paddingBottom: 2,
+  },
+  metaTwoLine: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'space-between',
     paddingBottom: 2,
   },
   metaItem: {