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/modules/core/routes/pages/store.py

@@ -9,11 +9,13 @@ Store pages for core functionality:
 """
 
 from fastapi import APIRouter, Depends, Request
-from fastapi.responses import HTMLResponse
+from fastapi.responses import HTMLResponse, RedirectResponse
 from sqlalchemy.orm import Session
 
 from app.api.deps import (
+    UserContext,
     get_current_store_from_cookie_or_header,
+    get_current_store_optional,
     get_db,
     get_resolved_store_code,
 )
@@ -24,6 +26,21 @@ from app.templates_config import templates
 router = APIRouter()
 
 
+# ============================================================================
+# STORE ROOT REDIRECT
+# ============================================================================
+
+
+@router.get("/", response_class=RedirectResponse, include_in_schema=False)
+async def store_root(
+    current_user: UserContext | None = Depends(get_current_store_optional),
+):
+    """Redirect /store/ based on authentication status."""
+    if current_user:
+        return RedirectResponse(url="/store/dashboard", status_code=302)
+    return RedirectResponse(url="/store/login", status_code=302)
+
+
 # ============================================================================
 # STORE DASHBOARD
 # ============================================================================