refactor

frontend/src/routes/+layout.svelte

@@ -1,3 +1,18 @@
+<!-- [DEF:frontend.src.routes.+layout:Module] -->
+<!--
+@TIER:      STANDARD
+@SEMANTICS: layout, root, navigation, sidebar, toast
+@PURPOSE:   Root layout component that provides global UI structure (Sidebar, Navbar, Footer, TaskDrawer, Toasts).
+@LAYER:     UI (Layout)
+@RELATION:  DEPENDS_ON -> Sidebar
+@RELATION:  DEPENDS_ON -> TopNavbar
+@RELATION:  DEPENDS_ON -> Footer
+@RELATION:  DEPENDS_ON -> Toast
+@RELATION:  DEPENDS_ON -> ProtectedRoute
+@RELATION:  DEPENDS_ON -> TaskDrawer
+@INVARIANT: All pages except /login are wrapped in ProtectedRoute.
+-->
+
 <!-- [DEF:layout:Module] -->
 <script>
     import '../app.css';
@@ -52,3 +67,4 @@
     {/if}
 </main>
 <!-- [/DEF:layout:Module] -->
+<!-- [/DEF:frontend.src.routes.+layout:Module] -->