feat: add vitest, vite, move to tdd

vite.config.ts

@@ -0,0 +1,30 @@
+import path from "path";
+import { builtinModules } from "node:module";
+import { defineConfig } from "vite";
+
+export default defineConfig({
+	build: {
+		target: "node20",
+		ssr: path.resolve(__dirname, "src/extension.ts"),
+		outDir: "out",
+		sourcemap: true,
+		rollupOptions: {
+			output: {
+				entryFileNames: "extension.js",
+			},
+			external: [
+				"vscode",
+				...builtinModules,
+				...builtinModules.map((m) => `node:${m}`),
+			],
+		},
+	},
+	ssr: {
+		noExternal: true,
+	},
+	resolve: {
+		alias: {
+			"@": path.resolve(__dirname, "src"),
+		},
+	},
+});