miscellaneous maintenance list

[seansfkelley]

• [ ] bump to React 18
• [ ] switch to react-jsx/react-jsxdev transform and change/remove React import style
• [ ] function-ify more components (especially those with weird lifecycle event usage)
• [ ] add linter
  • [ ] rules-of-hooks
  • [ ] import organization
  • [ ] eqeqeq
• [ ] bump to Parcel v2 (maybe)
• [ ] remove classname/ref kludge
• [ ] DRY up CSS: see if I can stop using the .disabled class and just use the state
• [ ] updated screenshots