feat(system-builder): stats, formula names and samples in a definitio…

[over2take]

…n (4b2a)

backend/systemBuilder/stats.js: a stats section of groups of stats (id, label, optional whole-number min and max, optional tie to another stat), checked for ids, labels, ranges, ties, limits (20 groups, 100 stats each) and clashes with formulas, the starter sheet's fields and the health section's; derived values may carry a label; samples holds the builder's sample character (numbers for the system's own stats).

The starter sheet shows each stat group as a section (after health, before DERIVED, ranges as hints), and derived values by their names. Decided with the user 2026-10-06 (mockup builder-stats-rules): the starter sheet had no boxes for stats, so a system couldn't work before the sheet designer.

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