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/loyalty/locales/de.json

@@ -90,5 +90,11 @@
         "view_rewards_desc": "Prämien und Einlösungen anzeigen",
         "manage_rewards": "Prämien verwalten",
         "manage_rewards_desc": "Treueprämien erstellen und verwalten"
+    },
+    "onboarding": {
+        "create_program": {
+            "title": "Treueprogramm erstellen",
+            "description": "Erstellen Sie Ihr erstes Stempel- oder Punkteprogramm"
+        }
     }
 }

app/modules/loyalty/locales/en.json

@@ -90,5 +90,11 @@
         "statistics": "Statistics",
         "overview": "Overview",
         "settings": "Settings"
+    },
+    "onboarding": {
+        "create_program": {
+            "title": "Create a loyalty program",
+            "description": "Set up your first stamp or points program"
+        }
     }
 }

app/modules/loyalty/locales/fr.json

@@ -90,5 +90,11 @@
         "view_rewards_desc": "Voir les récompenses et les échanges",
         "manage_rewards": "Gérer les récompenses",
         "manage_rewards_desc": "Créer et gérer les récompenses de fidélité"
+    },
+    "onboarding": {
+        "create_program": {
+            "title": "Créer un programme de fidélité",
+            "description": "Créez votre premier programme de tampons ou de points"
+        }
     }
 }

app/modules/loyalty/locales/lb.json

@@ -90,5 +90,11 @@
         "view_rewards_desc": "Belounungen an Aléisunge kucken",
         "manage_rewards": "Beloununge verwalten",
         "manage_rewards_desc": "Treiheet-Belounungen erstellen a verwalten"
+    },
+    "onboarding": {
+        "create_program": {
+            "title": "Treieprogramm erstellen",
+            "description": "Erstellt Äert éischt Stempel- oder Punkteprogramm"
+        }
     }
 }

app/modules/loyalty/services/loyalty_onboarding.py

@@ -26,8 +26,8 @@ class LoyaltyOnboardingProvider:
         return [
             OnboardingStepDefinition(
                 key="loyalty.create_program",
-                title_key="onboarding.loyalty.create_program.title",
-                description_key="onboarding.loyalty.create_program.description",
+                title_key="loyalty.onboarding.create_program.title",
+                description_key="loyalty.onboarding.create_program.description",
                 icon="gift",
                 route_template="/store/{store_code}/loyalty/programs",
                 order=300,

app/modules/loyalty/static/merchant/js/loyalty-settings.js

@@ -32,6 +32,9 @@ function merchantLoyaltySettings() {
             if (window._merchantLoyaltySettingsInitialized) return;
             window._merchantLoyaltySettingsInitialized = true;
 
+            // Load sidebar menu (from base data())
+            this.loadMenuConfig();
+
             await this.loadSettings();
             loyaltySettingsLog.info('=== MERCHANT LOYALTY SETTINGS PAGE INITIALIZATION COMPLETE ===');
         },