feat: add removable reference feature vertical slice

docs/architecture/starter-experience.md

@@ -11,7 +11,8 @@ primitives, and state surfaces remain reusable.
 validated config + coherent release manifest
   -> concrete adapters
   -> QueryClientProvider
-  -> BrowserRouter
+  -> ApplicationProvider
+  -> RouterProvider
   -> ThemeProvider
   -> SessionProvider
   -> AppShell
@@ -31,7 +32,7 @@ remain stable in the shell.
 | `EXAMPLES_UI` | `/examples/ui` | public | interactive primitives and tokens |
 | `EXAMPLES_STATES` | `/examples/states` | public | async and access state matrix |
 | `EXAMPLES_AUTH` | `/examples/auth` | public | session integration controls |
-| `SAMPLE_RESOURCE_LIST` | `/sample/resources` | integration-defined | protected integration seam |
+| `REFERENCE_RESOURCE_LIST` | `/examples/reference-resources` | integration-defined | removable vertical slice |
 | `NOT_FOUND` | `*` | public | safe navigation recovery |
 
 Navigation labels and order come from `ROUTE_REGISTRY`; the sidebar does not
@@ -54,24 +55,25 @@ 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
+The steps below describe the current extension path. 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`.
-3. Use application ports or use cases; do not import concrete adapters.
+1. Add a serializable contribution under the feature ownership boundary and
+   install it through `src/features/installed-feature-contracts.js`.
+2. Add the lazy component and route codecs through
+   `src/features/installed-feature-runtimes.tsx`.
+3. Compose feature application inputs and outbound gateways only through
+   `src/features/installed-feature-adapters.ts`.
 4. Use the semantic tokens, UI primitives, and state surfaces before adding a
    project-specific variant.
 5. Add component behavior, all-engine E2E, automated axe, and signed manual
    route evidence.
-6. Run `test:sample-removal` to prove the visible starter still builds without
-   `src/sample/contract-fixture`.
+6. Run `test:sample-removal` to prove the generic starter typechecks, passes
+   architecture/registry/tests/home smoke, and builds without the complete
+   reference feature.
 
 Theme preference is the public `COLOR_SCHEME` storage contract. Authentication
 tokens and other secrets remain forbidden storage keys.