Add Firefox support

[jsfr]

This change adds Firefox browser compatibility to the extension:

• Updated README.md: Added Firefox installation instructions section with manual installation steps for Firefox users, including notes about temporary add-on limitations and the need for Mozilla signing for permanent installation
• Updated manifest.json:
  • Removed Chrome-specific $schema field to improve cross-browser compatibility
  • Added browser_specific_settings configuration for Firefox (Gecko) with extension ID and minimum version requirement (Firefox 109.0+)

The extension now supports both Chrome and Firefox using the same manifest file (Manifest V3).

[ckob]

Hi @jsfr, thanks for your PR!
I'm about to merge and publish #16, which adds some runtime options. I've just updated it to use browser-polyfill instead of directly the chrome API. This way, at least the script should work for Firefox.
I'm not sure if the following part of the manifest would work in firefox too:

"background": {
  "service_worker": "background.js"
},

[jsfr]

Hi @jsfr, thanks for your PR! I'm about to merge and publish #16, which adds some runtime options. I've just updated it to use browser-polyfill instead of directly the chrome API. This way, at least the script should work for Firefox. I'm not sure if the following part of the manifest would work in firefox too:

"background": {
  "service_worker": "background.js"
},

I'm not too sure either, but I'm happy to investigate it and figure out what needs to be done once you're done with merging #16 :)

[jsfr]

I've updated the PR now with what I believe are the changes necessary. It's working in Firefox, but I have yet to test it on Chrome.

[ckob]

I've updated the PR now with what I believe are the changes necessary. It's working in Firefox, but I have yet to test it on Chrome.

Just tested it on Chrome. It works! But unfortunately there is a warning.

I think that the solution would be to have two manifest files. The firefox and the chrome one. Then do a Makefile/npm build for each browser taking the manifest.json that corresponds. I will do it soon 👍

Thanks!