feat: share a custom system as a .citysys file, and delete as a hide …

[over2take]

…that a reinstall undoes

A published system exports as one readable JSON file with a cover: name, author, version, the CITY_NET version it came from, license, and its origin, who the system is across servers. A file is read on the server as untrusted input: capped in size, checked like the editor's own work, text kept as text, and it never carries characters or sheets.

Installing is a preview that changes nothing, then new, update or keep both. An update only replaces a copy nobody has changed here, and never a system made here; keep both gives the copy its own id and origin, so the two never collide. Never a merge. A file with problems installs as a draft to fix, never as something a game can run.

Deleting now hides a system instead of removing it: it leaves every list and cannot be run, and reinstalling its file brings it back under its old id, with every character, bank and token health played in it. The preview warns when that would replace changes made here.

New custom_systems columns (origin, source_hash, deleted_at) are added on start; a system made before them is its own origin. Checked on a copy of a real database: nothing else changes.

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