feat(tenancy): add profile editing in merchant team edit modal

Edit modal now has editable first_name, last_name, email fields with
a "Save Profile" button, alongside the existing per-store role management.

New:
- PUT /merchants/account/team/members/{user_id}/profile endpoint
- MerchantTeamProfileUpdate schema
- update_team_member_profile() service method with ownership validation
- 2 new i18n keys across 4 locales (personal_info, save_profile)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/modules/tenancy/locales/lb.json

@@ -50,6 +50,8 @@
         "stores_and_roles": "Geschäfter & Rollen",
         "title": "Team",
         "total_members": "Memberen total",
+        "personal_info": "Perséinlech Informatiounen",
+        "save_profile": "Profil späicheren",
         "view_member": "Member kucken",
         "account_information": "Konto Informatiounen",
         "username": "Benotzernumm",