Bun's bundler mis-compiles `import * as tmp from 'tmp'`.

tmp's entrypoint ends with `Object.defineProperty(module.exports, 'tmpdir', {...})`.
When bun builds an ESM namespace object for that CJS module it emits a reference
to `exports_tmp` without ever declaring the binding, so the compiled binary dies
on startup with `ReferenceError: exports_tmp is not defined`.

Importing it as CJS instead keeps bun on its `__commonJS` path, which handles the
`defineProperty` pattern correctly. Only the `tmp.file` value and the `Options`
type are used here, so the switch is behaviour-preserving.

diff --git a/src/util/fs.ts b/src/util/fs.ts
index 21c99ef..0d2224f 100644
--- a/src/util/fs.ts
+++ b/src/util/fs.ts
@@ -1,6 +1,7 @@
 import * as fs from 'fs';
 import * as path from 'path';
-import * as tmp from 'tmp';
+import type { Options as TmpOptions } from 'tmp';
+const tmp: typeof import('tmp') = require('tmp');
 import { lookpath } from 'lookpath';
 import { isErrorLike } from '@httptoolkit/util';

@@ -62,7 +63,7 @@ export const resolveCommandPath = (path: string): Promise<string | undefined> =>
 export const commandExists = (path: string): Promise<boolean> =>
     resolveCommandPath(path).then((result) => result !== undefined);

-export const createTmp = (options: tmp.Options = {}) => new Promise<{
+export const createTmp = (options: TmpOptions = {}) => new Promise<{
     path: string,
     fd: number,
     cleanupCallback: () => void