make ci use the `bun.report` code to remap stack traces in PRs

[paperclover]

technique to add crash report decoding to bun ci

• test runner thing hosts a server on some port
• spawn all bun instances with the crash reporter environment variable
• the local server handles one url type (/<code>/ack)
• it calls remap from the bun.report codebase (this can be trivially installed via bun install )
• add the remapped stack trace to the CI log

reminder that bun.report is fully self-hostable (https://github.com/oven-sh/bun.report), as well as installable as a package via bun install. it also has some helper binaries in ./bin

specifically ./bin/remap allows --exe to use a custom binary path

Usage: remap <trace string> <opts>

Options:
  --md, display as github issue markdown
  --exe, path to executable

the code for this program is like 30 lines, most of it being arg parsing. it is a good reference.