docs(readme): list Push Notifications (FCM) as a paid-only feature

The paid Android README already markets push as "feature not included in
free version," but this repo's "Not Included in the Free Version" list
omitted it. The free app ships no FCM code (no push/ directory), so this
aligns the README with the actual feature boundary.

Author: dadachi

README.md

@@ -102,6 +102,7 @@ The full versions ([NativeAppTemplate-Android (Solo)](https://nativeapptemplate.
 - User Invitation to Organizations
 - Role-Based Permissions and Access Control
 - Organization Switching UI
+- Push Notifications via FCM
 
 ## Getting Started