feat: complete dynamic menu system across all frontends

- Add "Merchant Frontend" tab to admin menu-config page
- Merchant render endpoint now respects AdminMenuConfig visibility
  via get_merchant_primary_platform_id() platform resolution
- New store menu render endpoint (GET /store/core/menu/render/store)
  with platform-scoped visibility and store_code interpolation
- Store sidebar migrated from hardcoded Jinja2 macros to dynamic
  Alpine.js x-for rendering with loading skeleton and fallback
- Store init-alpine.js: add loadMenuConfig(), expandSectionForCurrentPage()
- Include store page route fixes, login template updates, and tests

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

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

@@ -3,6 +3,7 @@
 Core Store Page Routes (HTML rendering).
 
 Store pages for core functionality:
+- Dashboard
 - Media library
 - Notifications
 """
@@ -19,6 +20,35 @@ from app.templates_config import templates
 router = APIRouter()
 
 
+# ============================================================================
+# STORE DASHBOARD
+# ============================================================================
+
+
+@router.get(
+    "/{store_code}/dashboard", response_class=HTMLResponse, include_in_schema=False
+)
+async def store_dashboard_page(
+    request: Request,
+    store_code: str = Path(..., description="Store code"),
+    current_user: User = Depends(get_current_store_from_cookie_or_header),
+    db: Session = Depends(get_db),
+):
+    """
+    Render store dashboard.
+
+    JavaScript will:
+    - Load store info via API
+    - Load dashboard stats via API
+    - Load recent orders via API
+    - Handle all interactivity
+    """
+    return templates.TemplateResponse(
+        "core/store/dashboard.html",
+        get_store_context(request, db, current_user, store_code),
+    )
+
+
 # ============================================================================
 # MEDIA LIBRARY
 # ============================================================================