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/checkout/routes/api/storefront.py

@@ -11,7 +11,6 @@ Requires customer authentication for order placement.
 """
 
 import logging
-from datetime import UTC, datetime
 
 from fastapi import APIRouter, Depends, Request
 from sqlalchemy.orm import Session
@@ -92,15 +91,21 @@ def place_order(
         },
     )
 
-    # Update customer stats
-    customer.total_orders = (customer.total_orders or 0) + 1
-    customer.total_spent = (customer.total_spent or 0) + order.total_amount
-    customer.last_order_date = datetime.now(UTC)
-    db.flush()
+    # Update customer order stats (owned by orders module)
+    from app.modules.orders.services.customer_order_service import (
+        customer_order_service,
+    )
+
+    stats = customer_order_service.record_order(
+        db=db,
+        store_id=store.id,
+        customer_id=customer.id,
+        total_amount_cents=order.total_amount_cents,
+    )
 
     logger.debug(
-        f"Updated customer stats: total_orders={customer.total_orders}, "
-        f"total_spent={customer.total_spent}"
+        f"Updated customer order stats: total_orders={stats.total_orders}, "
+        f"total_spent_cents={stats.total_spent_cents}"
     )
 
     # Clear cart (get session_id from request cookies or headers)