add subDirectory option, move @ to # in relative paths, fix builder

tsup.config.ts

@@ -0,0 +1,29 @@
+import { defineConfig } from "tsup";
+
+export default defineConfig({
+	entry: ["src/index.ts"],
+	format: ["esm", "cjs"],
+	dts: {
+		resolve: true,
+		compilerOptions: {
+			module: "ESNext",
+			moduleResolution: "bundler",
+		},
+	},
+	outDir: "dist",
+	minify: true,
+	splitting: false,
+	sourcemap: false,
+	clean: true,
+	treeshake: true,
+	target: "es2024",
+	define: {
+		"process.env.NODE_ENV": '"production"',
+	},
+	outExtension({ format }) {
+		return {
+			js: format === "cjs" ? ".cjs" : ".js",
+			dts: ".d.ts",
+		};
+	},
+});