[APP-834] Allow @ing someone in post directly from profile (#1241)

* setup `initMention` for mobile

* setup creating post with profile tagged on web

src/view/shell/Composer.tsx

@@ -14,6 +14,7 @@ export const Composer = observer(
     onPost,
     onClose,
     quote,
+    mention,
   }: {
     active: boolean
     winHeight: number
@@ -21,6 +22,7 @@ export const Composer = observer(
     onPost?: ComposerOpts['onPost']
     onClose: () => void
     quote?: ComposerOpts['quote']
+    mention?: ComposerOpts['mention']
   }) => {
     const pal = usePalette('default')
     const initInterp = useAnimatedValue(0)
@@ -65,6 +67,7 @@ export const Composer = observer(
           onPost={onPost}
           onClose={onClose}
           quote={quote}
+          mention={mention}
         />
       </Animated.View>
     )