improve: issues design

[leeoocca]

Some old code... Scope is more or less:

• issue list
  • [x] cards instead table
  • [x] show excerpt
  • [x] ascending/descending toggle
  • [x] mobile layout
• issue details
  • [x] issue header/title
  • [x] hide longer infobox description under a <details>
  • [x] comment design
• new issue
  • [x] header
  • [x] fix labels
  • [x] info box one line
• contact
  • [x] fix labels

Fixes #160, fixes #167

[leeoocca]

Fixed error boundary in 14fdd51

(before it showed an extra navbar)

[leeoocca]

I'm trying to implement a pretty version of https://github.com/42-student-council/website/issues/167#issuecomment-2318129689

[leeoocca]

run-prettier

[leeoocca]

New issues list design:

[leeoocca]

The purple might still be too dark in dark mode, similarly to #209