Initial implementation of jrx - JSX factory for json-render

JSX factory that compiles JSX trees into json-render Spec JSON.
Framework-agnostic custom jsx-runtime, no React dependency at runtime.

- jsx/jsxs/Fragment via jsxImportSource: "jrx"
- render() flattens JrxNode tree into { root, elements, state? } Spec
- Auto key generation (type-N) with explicit key override
- Full feature parity: visible, on, repeat, watch as reserved props
- Function components via component() or plain functions
- @json-render/core as peer dependency

Co-authored-by: Ona <no-reply@ona.com>

src/test-preload.ts

@@ -0,0 +1,18 @@
+import { Window } from "happy-dom";
+
+const window = new Window({ url: "http://localhost" });
+
+// Register DOM globals for @testing-library/react
+for (const key of Object.getOwnPropertyNames(window)) {
+  if (!(key in globalThis)) {
+    Object.defineProperty(globalThis, key, {
+      value: (window as unknown as Record<string, unknown>)[key],
+      writable: true,
+      configurable: true,
+    });
+  }
+}
+
+Object.defineProperty(globalThis, "window", { value: window, writable: true, configurable: true });
+Object.defineProperty(globalThis, "document", { value: window.document, writable: true, configurable: true });
+Object.defineProperty(globalThis, "navigator", { value: window.navigator, writable: true, configurable: true });