Ensure and test that running in the browser is appropriately supported

[NullVoxPopuli]

Use case (for me, anyway):

• https://limber.glimdown.com/
• https://tutorial.glimdown.com/
• https://ember-primitives.pages.dev/

This would fix an issue with Safari, where my copied ember-template-imports code's regex is not compatible with Safari.

We'll need to make sure no "extra stuff" (plugins, etc) are included in the build as browsers are more sensitive to extraneous bytes (on the embroider call today, Ed mentioned that he thinks this is already happening 🎉 ).

[NullVoxPopuli]

Confirm that this isn't currently compatible with the browser:

const path = require('path').join(__dirname, 'content_tag_bg.wasm');
const bytes = require('fs').readFileSync(path);

neither path, nor fs exists in the browser.

So, we probably need to tweak how content-tag is compiled to support both.

Test PR here: NullVoxPopuli/limber#1162