feat(tenancy): add merchant team CRUD with multi-store hub view

The merchant team page was read-only. Now merchant owners can invite,
edit roles, and remove team members across all their stores from a
single hub view.

Architecture: No new models — delegates to existing store_team_service.
Members are deduplicated across stores with per-store role badges.

New:
- 5 API endpoints: GET team (member-centric), GET store roles, POST
  invite (multi-store), PUT update role, DELETE remove member
- merchant-team.js Alpine component with invite/edit/remove modals
- Full CRUD template with stats cards, store filter, member table
- 7 Pydantic schemas for merchant team request/response
- 2 service methods: validate_store_ownership, get_merchant_team_members
- 25 new i18n keys across 4 tenancy locales + 1 core common key

Tests: 434 tenancy tests passing, arch-check green.

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

app/modules/tenancy/locales/fr.json

@@ -12,20 +12,45 @@
         "team": "Équipe"
     },
     "team": {
-        "title": "Équipe",
-        "members": "Membres",
+        "actions": "Actions",
+        "active": "Actifs",
         "add_member": "Ajouter un membre",
+        "all_stores": "Tous les magasins",
+        "edit_member": "Modifier le membre",
+        "editor": "Éditeur",
+        "email": "E-mail",
+        "email_placeholder": "Saisir l'adresse e-mail",
+        "error_title": "Erreur lors du chargement",
+        "first_name": "Prénom",
+        "invite_first_member": "Invitez votre premier membre",
         "invite_member": "Inviter un membre",
+        "invitation_accepted": "Invitation acceptée",
+        "invitation_sent": "Invitation envoyée",
+        "last_name": "Nom de famille",
+        "loading_team": "Chargement de l'équipe...",
+        "manage_members_description": "Gérer les membres de l'équipe sur tous vos magasins",
+        "manager": "Gestionnaire",
+        "member": "Membre",
+        "member_stores": "Magasins du membre",
+        "members": "Membres",
+        "no_members_description": "Invitez des membres pour gérer vos magasins",
+        "no_members_title": "Aucun membre encore",
+        "no_role": "Aucun rôle",
+        "owner": "Propriétaire",
+        "pending_invitations": "Invitations en attente",
+        "permissions": "Permissions",
+        "remove_confirmation": "Êtes-vous sûr de vouloir supprimer",
+        "remove_from_all_stores": "Supprimer de tous les magasins",
         "remove_member": "Retirer un membre",
         "role": "Rôle",
-        "owner": "Propriétaire",
-        "manager": "Gestionnaire",
-        "editor": "Éditeur",
-        "viewer": "Lecteur",
-        "permissions": "Permissions",
-        "pending_invitations": "Invitations en attente",
-        "invitation_sent": "Invitation envoyée",
-        "invitation_accepted": "Invitation acceptée"
+        "select_stores": "Sélectionner les magasins",
+        "send_invitation": "Envoyer l'invitation",
+        "status": "Statut",
+        "store_roles": "Rôles par magasin",
+        "stores_and_roles": "Magasins et rôles",
+        "title": "Équipe",
+        "total_members": "Membres totaux",
+        "viewer": "Lecteur"
     },
     "messages": {
         "business_info_saved": "Business info saved",