Require loading as a module

The issue is wgsl_reflect defines `class Function`. If this code
is loaded as a non-module then that ends up overriding the default
`Function` class and code that's checking `... instanceof Function`
starts failing.

There's no easy way for a script to check if it was loaded as a
module or a non-module but using `import.meta` ends up requiring
it to be loaded as a module.

src/webgpu-debug-helper.ts

@@ -6,3 +6,7 @@ import './compute-pass-encoder.js';
 import './render-pass-encoder.js';
 import './render-bundle-encoder.js';
 import './texture.js';
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+const _ = import.meta; // webgpu-debug-helper must be imported as a module with import or `<script type="module" ...>`
+console.log('webgpu-debug-helper loaded:', _ !== undefined);