✨(react) add tokens.ts files handling

These files will be used to define the custom design tokens per components.
They are automatically aggregated by the packages/react/cunningham.ts file,
this is why handling typescript config file was important.

packages/react/src/components/Button/index.spec.tsx

@@ -1,12 +1,20 @@
 import { describe, expect, it } from "vitest";
 import { render, screen } from "@testing-library/react";
 import React from "react";
+import { buildTheme, loadTokens } from "tests/Theme";
 import { Button } from "./index";
 
 describe("<Button/>", () => {
   it("renders", () => {
-    render(<Button />);
-    const button = screen.getByRole("button", { name: "<Button/>" });
+    render(<Button>Test button</Button>);
+    const button = screen.getByRole("button", { name: "Test button" });
     expect(button.classList.contains("c__button")).toBe(true);
   });
+
+  it("uses custom token", async () => {
+    await buildTheme();
+    const tokens = await loadTokens();
+    expect(tokens.components.button["border-radius"]).toBeDefined();
+    expect(tokens.components.button.shadow).toBeDefined();
+  });
 });