feat(sync): follow the visit sync on the dashboard

Show the "Syncing with Steam" badge while a visit sync runs, then
reload the sync changes banner and the library.

src/utils/syncChanges.js

@@ -28,7 +28,7 @@ export const markSyncChangesSeen = (syncedAt) =>
 /**
  * What the dashboard shows of a result: null (nothing), `{mode: 'nothing'}` for a manual sync that changed nothing, or
  * `{mode: 'changes', imported, added, removed, minutes, achievements, moves}`. A result the user saw, and an empty
- * result of an automatic sync, show nothing.
+ * result of an automatic or a visit sync, show nothing.
  */
 export function bannerOf(result) {
     if (!result || result.seen) return null;