feat: add vitest, vite, move to tdd

vitest.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from "vitest/config";
+import path from "path";
+
+export default defineConfig({
+	test: {
+		include: ["src/**/*.test.ts", "tests/**/*.test.ts"],
+		exclude: ["node_modules", "out"],
+		environment: "node",
+	},
+	resolve: {
+		alias: {
+			"@": path.resolve(__dirname, "src"),
+		},
+	},
+});