feat(tenancy): add resend invitation for pending team members

New resend_invitation() service method regenerates the token and
resends the invitation email for pending members.

Available on all frontends:
- Merchant: POST /merchants/account/team/stores/{sid}/members/{uid}/resend
- Store: POST /store/team/members/{uid}/resend

UI: paper-airplane icon appears on pending members in both merchant
and store team pages.

i18n: resend_invitation + invitation_resent keys in 4 locales.
Also translated previously untranslated invitation_sent_successfully
in fr/de/lb.

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

app/modules/tenancy/static/merchant/js/merchant-team.js

@@ -226,6 +226,31 @@ function merchantTeam() {
             }
         },
 
+        /**
+         * Resend invitation to a pending member
+         */
+        async resendInvitation(member) {
+            if (!member.stores || member.stores.length === 0) return;
+
+            this.saving = true;
+            try {
+                // Resend for the first pending store
+                const pendingStore = member.stores.find(s => s.is_pending) || member.stores[0];
+                await apiClient.post(
+                    `/merchants/account/team/stores/${pendingStore.store_id}/members/${member.user_id}/resend`
+                );
+
+                Utils.showToast(I18n.t('tenancy.messages.invitation_resent'), 'success');
+                merchantTeamLog.info('Resent invitation to:', member.email);
+                await this.loadTeamData();
+            } catch (error) {
+                merchantTeamLog.error('Failed to resend invitation:', error);
+                Utils.showToast(error.message || 'Failed to resend invitation', 'error');
+            } finally {
+                this.saving = false;
+            }
+        },
+
         /**
          * Update member role for a specific store
          */