feat: add CheckPagePermission plug for page-level authorization

- Plug checks PermissionSets page list; redirects unauthorized to profile or sign-in.
- Router: add plug to :browser pipeline; LiveHelpers: check_page_permission_on_params
  for client-side navigation (push_patch).

lib/mv_web/router.ex

@@ -14,6 +14,7 @@ defmodule MvWeb.Router do
     plug :put_secure_browser_headers
     plug :load_from_session
     plug :set_locale
+    plug MvWeb.Plugs.CheckPagePermission
   end
 
   pipeline :api do
@@ -48,7 +49,8 @@ defmodule MvWeb.Router do
     ash_authentication_live_session :authentication_required,
       on_mount: [
         {MvWeb.LiveUserAuth, :live_user_required},
-        {MvWeb.LiveHelpers, :ensure_user_role_loaded}
+        {MvWeb.LiveHelpers, :ensure_user_role_loaded},
+        {MvWeb.LiveHelpers, :check_page_permission_on_params}
       ] do
       live "/", MemberLive.Index, :index