feat(system-builder): live formula values from the sample character (…

[over2take]

…4b2b)

derived.previewDerived works out a draft's derived values from data (the sample character), leaving out each value with a problem and everything that reads one, round by round, so one unfinished formula doesn't blank the rest; it returns compileSystem's problems too. A problem it can't pin to one named value (a broken table) gives no values, only the problems.

POST /api/systems/preview-values {definition}, main admin only: refuses what can't be a definition, uses the draft's own samples, changes nothing. One engine for the builder and the game, rather than a second copy in the browser (which would also need the code-backed $rules).

Summary

Test plan

• Tested locally
• Tests pass

Pre-merge checklist

Code quality:

• Code follows project style
• No breaking changes (or clearly documented)
• No console errors or warnings

Version & Release:

• Version bumped? If releasing to users, update:
  • frontend/package.json version
  • docker-compose.yml APP_VERSION
  • CHANGELOG.md with release notes
• GitHub Actions will auto-tag Docker images with the new version

Before merging to main:

• All tests passing
• PR reviewed and approved
• Branch is up to date with main
• No merge conflicts

Related issues