Firefox MV3

[r2dev2]

Adds support for MV3 in Firefox. Some things to note:

Problems

1. ff does not support service workers in their mv3 "support"
2. ff does not support extension to content script channels in their mv3 "support"

Solutions

1. use bg script for ff and service workers for chrome
   • implies that chrome and ff need completely different manifests (one is not superset of other)
   • introduce yarn dev:firefox and yarn dev:chrome and make yarn start alias for yarn dev:chrome
2. proxy extension to content script messages through background script for ff
   • unsure how long bg script for ff persists, I think it should stay up as long as chat is active?
   • should give to ff beta testers to make sure it actually works over long intervals

[KentoNishi]

can you swap yarn build to be chrome by default and add a yarn build:firefox instead?

[r2dev2]

can you swap yarn build to be chrome by default and add a yarn build:firefox instead?

Done in aa99119

[KentoNishi]

u forgot to update the readme

[r2dev2]

u forgot to update the readme

a7eccb8