SSR migrated to Rust

cores/mizan-rust-ssr/tests/fixture/Hello.js

@@ -0,0 +1,7 @@
+import { createElement } from "react"
+
+// A trivial component: props in, element out. The keystone only needs to prove
+// a real React tree renders to HTML inside a bare JS context.
+export function Hello({ name }) {
+  return createElement("div", { id: "greeting" }, `Hello, ${name}!`)
+}