Improve Sandbox Reloading

[justintaylor-dev]

While the UI HMR is very fast, currently reloading the Sandbox code.js is very slow since it's waiting on @adobe/ccweb-add-on-scripts to rebuild and reserve the plugin. Takes about 3-4 seconds.

See if there's a way to either:

• Update the code.js outside of ccweb-add-on-scripts and reload the addon sandbox from within the addon itself

or

• Bypass ccweb-add-on-scripts altogether so we have full control.

Have tried this on the custom-server branch, but there must be some secret sauce happening in the background. Even after serving the index.json as the script does over HTTPS, Express still doesn't want load the addon unless it's being hosted by ccweb-add-on-scripts

[justintaylor-dev]

Appears that @adobe/create-ccweb-add-on sends a WebSocket message to notify Express to reload the panel. I think this has to come from the some port that's being served.

https://github.com/adobe/create-ccweb-add-on/blob/9693b492c082fb3a8be32d440028bc5a7d7f1b24/packages/wxp-scripts/src/app/WxpSocketServer.ts#L165

Message 1

Message 2

[justintaylor-dev]

Update to copy has sped this up somewhat, takes about 2s instead of 4s to reload backend code now

c6df1da