feat(storefront): homepage, module gating, widget protocol, i18n fixes

Storefront homepage & module gating:
- CMS owns storefront GET / (slug="home" with 3-tier resolution)
- Catalog loses GET / (keeps /products only)
- Store root redirect (GET / → /store/dashboard or /store/login)
- Route gating: non-core modules return 404 when disabled for platform
- Seed store default homepages per platform

Widget protocol for customer dashboard:
- StorefrontDashboardCard contract in widgets.py
- Widget aggregator get_storefront_dashboard_cards()
- Orders and Loyalty module widget providers
- Dashboard template renders contributed cards (no module names)

Landing template module-agnostic:
- CTAs driven by storefront_nav (not hardcoded module names)
- Header actions check nav item IDs (not enabled_modules)
- Remove hardcoded "Add Product" sidebar button
- Remove all enabled_modules checks from storefront templates

i18n fixes:
- Title placeholder resolution ({{store_name}}) for store default pages
- Storefront nav label_keys prefixed with module code
- Add storefront.account.* keys to 6 modules (en/fr/de/lb)
- Header/footer CMS pages use get_translated_title(current_language)
- Footer labels use i18n keys instead of hardcoded English

Icon cleanup:
- Standardize on map-pin (remove location-marker alias)
- Replace all location-marker references across templates and docs

Docs:
- Storefront builder vision proposal (6 phases)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/api/deps.py

@@ -1744,3 +1744,39 @@ def get_current_customer_optional(
     except Exception:
         # Invalid token, store mismatch, or other error
         return None
+
+
+# =============================================================================
+# STOREFRONT MODULE GATING
+# =============================================================================
+
+
+def make_storefront_module_gate(module_code: str):
+    """
+    Create a FastAPI dependency that gates storefront routes by module enablement.
+
+    Used by main.py at route registration time: each non-core module's storefront
+    router gets this dependency injected automatically. The framework already knows
+    which module owns each route via RouteInfo.module_code — no hardcoded path map.
+
+    Args:
+        module_code: The module code to check (e.g. "catalog", "orders", "loyalty")
+
+    Returns:
+        A FastAPI dependency function
+    """
+
+    async def _check_module_enabled(
+        request: Request,
+        db: Session = Depends(get_db),
+    ) -> None:
+        from app.modules.service import module_service
+
+        platform = getattr(request.state, "platform", None)
+        if not platform:
+            return  # No platform context — let other middleware handle it
+
+        if not module_service.is_module_enabled(db, platform.id, module_code):
+            raise HTTPException(status_code=404, detail="Page not found")
+
+    return _check_module_enabled