feat: establish TypeScript-aware frontend tooling

tests/component/typescript-tooling-smoke.test.tsx

@@ -0,0 +1,20 @@
+// @vitest-environment jsdom
+
+import { render, screen } from "@testing-library/react";
+import { describe, expect, it } from "vitest";
+
+type StatusProps = Readonly<{
+  label: string;
+  tone: "neutral" | "positive";
+}>;
+
+function Status({ label, tone }: StatusProps) {
+  return <output data-tone={tone}>{label}</output>;
+}
+
+describe("TSX test tooling", () => {
+  it("parses, lints, type-checks, and renders TSX", () => {
+    render(<Status label="ready" tone="positive" />);
+    expect(screen.getByText("ready")).toHaveAttribute("data-tone", "positive");
+  });
+});