fix(storefront-i18n): dashboard widgets translate + correct customer-module key paths

Two bugs from Test 5.1 on FR storefront dashboard:

1. Loyalty + Orders dashboard cards (`StorefrontDashboardCard.title`/
   `subtitle`/`value_label`) were hardcoded English. Added `language`
   to `WidgetContext`; customer dashboard route passes
   `request.state.language` through; loyalty and orders widget
   providers now call `translate(..., context.language)` with new
   `widget.*` i18n keys × 4 locales each.

2. Customer-module locale JSON has redundant top-level `customers`
   wrapper, so after the module-locale loader auto-namespaces under
   module code `customers`, the actual key path is
   `customers.customers.customer_number` (matches the existing
   `loyalty.loyalty.wallet.apple` pattern). My earlier sweep used the
   single-prefix path for 8 references — fixed all to double-prefix.

Both bugs were visible end-of-day yesterday after the api container
recreate landed `1bade6e6`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/modules/orders/locales/fr.json

@@ -1,4 +1,11 @@
 {
+    "widget": {
+        "summary": {
+            "title": "Commandes",
+            "subtitle": "Voir l'historique des commandes",
+            "value_label": "Total des commandes"
+        }
+    },
     "orders": {
         "title": "Commandes",
         "order": "Commande",