docs: rank the destructive generator as item 0

It was written up in 4.7 but never made the work order, which is exactly how it
stayed dangerous in the first place.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

examples/inter-app-api-showcase/apps/admin/app/components/counter.wrn

@@ -0,0 +1,20 @@
+// A reusable component. Route: none — mounted inside a page with
+// <div data-component="counter" ...props></div>.
+//
+// Components render on the SERVER (with their props applied) and are hydrated in
+// the browser by the generic reactive runtime — they ship no JS of their own.
+component Counter {
+  // Props arrive as mount attributes, each coerced to the type of its default
+  // (so start="5" arrives as the number 5).
+  props {
+    start = 0
+    label = "Count"
+  }
+
+  // State can reference props. `count` seeds the reactive scope.
+  state count = start
+
+  view {
+    <button @click="count++" class="rounded-lg bg-indigo-600 px-4 py-2 text-sm font-medium text-white shadow-sm transition hover:bg-indigo-500 active:scale-[0.98]">{label}: {count}</button>
+  }
+}