Fix postbuild esbuild resolution by using Vite

scripts/postbuild.mjs

@@ -1,5 +1,5 @@
 import { copyFileSync, readFileSync, writeFileSync } from "node:fs";
-import { transform } from "esbuild";
+import { transformWithEsbuild } from "vite";
 
 // vite-plugin-dts emits a single bundled declaration file. Copy it to the
 // ESM/CJS-specific extensions so each `exports` condition resolves to types
@@ -9,7 +9,11 @@ copyFileSync(source, "dist/driver.js.d.mts");
 copyFileSync(source, "dist/driver.js.d.cts");
 
 // Vite ships the ESM bundle with its whitespace intact (the CJS and IIFE builds
-// are already minified), so strip it here for a smaller gzipped file.
+// are already minified), so strip it here for a smaller gzipped file. Reuses
+// Vite's own esbuild so the build pulls in no extra dependency.
 const esmBundle = "dist/driver.js.mjs";
-const minified = await transform(readFileSync(esmBundle, "utf8"), { minify: true, legalComments: "none" });
-writeFileSync(esmBundle, minified.code);
+const { code } = await transformWithEsbuild(readFileSync(esmBundle, "utf8"), esmBundle, {
+  minify: true,
+  legalComments: "none",
+});
+writeFileSync(esmBundle, code);