Billing upgrade/downgrade, inviti in app e diretta YouTube da mobile.

Upgrade Stripe con addebito immediato; downgrade programmato a fine periodo.
UX billing più sobria con box info; icone piani. API inviti e OAuth YouTube
per staff trasmissione; deep link join; scelta partita programmata o nuova.

Co-authored-by: Cursor <cursoragent@cursor.com>

mobile/pubspec.yaml

@@ -1,7 +1,7 @@
 name: match_live_tv
 description: Match Live TV - Lo streaming che non muore
 publish_to: 'none'
-version: 1.1.0+2
+version: 1.2.0+3
 
 environment:
   sdk: ^3.12.0
@@ -25,6 +25,7 @@ dependencies:
   shared_preferences: ^2.5.3
   url_launcher: ^6.3.1
   share_plus: ^10.1.4
+  app_links: ^6.4.0
 
 dev_dependencies:
   flutter_test: