fix(ui): per-bot invite caption + friendly self-redeem note

- The share caption is now in the bot's language: 'Давай играть в Эрудит!' (ru bot),
  "Let's play Scrabble!" (en bot) — picked by the session service language, not the
  interface language.
- Redeeming your own invite (deep link or manual) no longer shows the scary
  'can't do that to yourself' error; it shows a friendly neutral note instead.

ui/src/lib/i18n/en.ts

@@ -234,8 +234,9 @@ export const en = {
   'friends.copy': 'Copy',
   'friends.codeCopied': 'Code copied.',
   'friends.shareTelegram': 'Share via Telegram',
-  'friends.inviteText': "Let's be friends in Scrabble!",
+  'friends.inviteText': "Let's play Scrabble!",
   'friends.linkCopied': 'Link copied.',
+  'friends.selfInvite': "Hopefully you've been friends with yourself for a while ☺️",
   'friends.added': 'Added {name}.',
   'friends.blockedList': 'Blocked players',
   'friends.unblock': 'Unblock',