feat: storefront subscription access guard + module-driven nav + URL rename

Add StorefrontAccessMiddleware that blocks storefront access for stores
without an active subscription, returning a multilingual unavailable page
(en/fr/de/lb) for page requests and JSON 403 for API requests. Multi-platform
aware: resolves subscription for detected platform with fallback to primary.

Also includes yesterday's session work:
- Module-driven storefront navigation via FrontendType.STOREFRONT menu declarations
- shop/ → storefront/ URL rename across 30+ templates
- Subscription context (tier_code) passed to storefront templates

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

app/modules/loyalty/definition.py

@@ -168,6 +168,22 @@ loyalty_module = ModuleDefinition(
                 ],
             ),
         ],
+        FrontendType.STOREFRONT: [
+            MenuSectionDefinition(
+                id="account",
+                label_key=None,
+                order=10,
+                items=[
+                    MenuItemDefinition(
+                        id="loyalty",
+                        label_key="storefront.account.loyalty",
+                        icon="gift",
+                        route="storefront/account/loyalty",
+                        order=60,
+                    ),
+                ],
+            ),
+        ],
     },
     is_core=False,  # Loyalty can be disabled
     # =========================================================================

app/modules/loyalty/templates/loyalty/storefront/dashboard.html

@@ -9,7 +9,7 @@
 <div class="max-w-4xl mx-auto px-4 sm:px-6 lg:px-8 py-8">
     <!-- Page Header -->
     <div class="mb-8">
-        <a href="{{ base_url }}shop/account/dashboard" class="inline-flex items-center text-sm text-gray-600 dark:text-gray-400 hover:text-primary mb-4">
+        <a href="{{ base_url }}storefront/account/dashboard" class="inline-flex items-center text-sm text-gray-600 dark:text-gray-400 hover:text-primary mb-4">
             <span x-html="$icon('arrow-left', 'w-4 h-4 mr-2')"></span>
             Back to Account
         </a>
@@ -26,7 +26,7 @@
         <span x-html="$icon('gift', 'w-16 h-16 mx-auto text-gray-300 dark:text-gray-600')"></span>
         <h2 class="mt-4 text-xl font-semibold text-gray-900 dark:text-white">Join Our Rewards Program!</h2>
         <p class="mt-2 text-gray-600 dark:text-gray-400">Earn points on every purchase and redeem for rewards.</p>
-        <a href="{{ base_url }}shop/loyalty/join"
+        <a href="{{ base_url }}storefront/loyalty/join"
            class="mt-6 inline-flex items-center px-6 py-3 text-sm font-medium text-white rounded-lg"
            style="background-color: var(--color-primary)">
             <span x-html="$icon('plus', 'w-5 h-5 mr-2')"></span>
@@ -125,7 +125,7 @@
         <div>
             <div class="flex items-center justify-between mb-4">
                 <h2 class="text-xl font-semibold text-gray-900 dark:text-white">Recent Activity</h2>
-                <a href="{{ base_url }}shop/account/loyalty/history"
+                <a href="{{ base_url }}storefront/account/loyalty/history"
                    class="text-sm font-medium hover:underline" style="color: var(--color-primary)">
                     View All
                 </a>

app/modules/loyalty/templates/loyalty/storefront/enroll-success.html

@@ -62,12 +62,12 @@
 
         <!-- Actions -->
         <div class="space-y-3">
-            <a href="{{ base_url }}shop/account/loyalty"
+            <a href="{{ base_url }}storefront/account/loyalty"
                class="block w-full py-3 px-4 text-white font-semibold rounded-lg transition-colors text-center"
                style="background-color: var(--color-primary)">
                 View My Loyalty Dashboard
             </a>
-            <a href="{{ base_url }}shop"
+            <a href="{{ base_url }}storefront"
                class="block w-full py-3 px-4 text-gray-700 dark:text-gray-300 font-medium rounded-lg border border-gray-300 dark:border-gray-600 hover:bg-gray-50 dark:hover:bg-gray-700 transition-colors text-center">
                 Continue Shopping
             </a>