prevent formatting errors from being published

[interim17]

Description

Formatting errors (already flagged by prettier) can break functionality on the admin page when published.

Expected Behavior

Errors/warnings flagged by prettier and linting tools should prevent publishing.

Tasks:

• configure prettier in repo and define formatting scripts in package.json, one for a check and one for writing
• define a gh action to run the check
• format the whole repo according to config
• optionally either have gh action run the formatting write script, or block merging to main when check fails