feat: multi-module improvements across merchant, store, i18n, and customer systems

- Fix platform-grouped merchant sidebar menu with core items at root level
- Add merchant store management (detail page, create store, team page)
- Fix store settings 500 error by removing dead stripe/API tab
- Move onboarding translations to module-owned locale files
- Fix onboarding banner i18n with server-side rendering + context inheritance
- Refactor login language selectors to use languageSelector() function (LANG-002)
- Move HTTPException handling to global exception handler in merchant routes (API-003)
- Add language selector to all login pages and portal headers
- Fix customer module: drop order stats from customer model, add to orders module
- Fix admin menu config visibility for super admin platform context
- Fix storefront auth and layout issues
- Add missing i18n translations for onboarding steps (en/fr/de/lb)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/orders/services/customer_order_service.py

@@ -13,10 +13,11 @@ Similar to how:
 """
 
 import logging
+from datetime import UTC, datetime
 
 from sqlalchemy.orm import Session
 
-from app.modules.orders.models import Order
+from app.modules.orders.models import CustomerOrderStats, Order
 
 logger = logging.getLogger(__name__)
 
@@ -89,6 +90,51 @@ class CustomerOrderService:
             .all()
         )
 
+    def record_order(
+        self,
+        db: Session,
+        store_id: int,
+        customer_id: int,
+        total_amount_cents: int,
+    ) -> CustomerOrderStats:
+        """
+        Record an order in customer order stats (upsert).
+
+        Args:
+            db: Database session
+            store_id: Store ID
+            customer_id: Customer ID
+            total_amount_cents: Order total in cents
+
+        Returns:
+            Updated CustomerOrderStats
+        """
+        stats = (
+            db.query(CustomerOrderStats)
+            .filter(
+                CustomerOrderStats.store_id == store_id,
+                CustomerOrderStats.customer_id == customer_id,
+            )
+            .first()
+        )
+        now = datetime.now(UTC)
+        if stats:
+            stats.total_orders = (stats.total_orders or 0) + 1
+            stats.total_spent_cents = (stats.total_spent_cents or 0) + total_amount_cents
+            stats.last_order_date = now
+        else:
+            stats = CustomerOrderStats(
+                store_id=store_id,
+                customer_id=customer_id,
+                total_orders=1,
+                total_spent_cents=total_amount_cents,
+                first_order_date=now,
+                last_order_date=now,
+            )
+            db.add(stats)
+        db.flush()
+        return stats
+
     def get_order_count(
         self,
         db: Session,