docs: audit frontend platform capabilities

docs/architecture/starter-experience.md

@@ -11,9 +11,9 @@ primitives, and state surfaces remain reusable.
 validated config + coherent release manifest
   -> concrete adapters
   -> QueryClientProvider
+  -> BrowserRouter
   -> ThemeProvider
   -> SessionProvider
-  -> BrowserRouter
   -> AppShell
   -> lazy route boundary
 ```
@@ -54,6 +54,14 @@ An external owner implements `readState`, `subscribe`, `beginSignIn`,
 
 ## Extending the starter
 
+The steps below describe the current extension path. The platform review found
+that several route metadata fields and the composed application facade are not
+yet connected end to end. New platform work should follow
+[routing, page templates, and reusable patterns](./routing-pages-and-patterns.md)
+and the
+[TypeScript, state, and data-flow target](./typescript-state-and-data-flow.md)
+rather than adding another independent route or data-loading convention.
+
 1. Register the route path, access hint, title, chunk, loading surface, error
    surface, and optional navigation metadata in `src/contracts/routes.js`.
 2. Add a lazy page in `src/presentation/` and render it through `RouteSurface`.