feat(system-builder): the FEATURES page, parts and shops (4b1c1)

[over2take]

components/FeaturesPage.tsx, from the approved mockup builder-words-features (2026-10-06): a switch per part with what it does; XP awards, death saves, luck and PDF import off and greyed as not used by custom systems yet; SHOPS opens out (while on) to shop buildings, catalogues and other buildings: rename (blank = the app's), on/off, and a catalogue's currency when the system has any; catalogues whose part is off greyed. BuilderScreen shows it on FEATURES; the bank's settings follow in 4b1c2.

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