feat(system-builder): SYSTEMS.EXE window and its GAME-tab button (4a1c1)

[over2take]

components/SystemsWindow.tsx, a TerminalWindow with the SYSTEMS folder: every system with its badges, the picked one's facts (name, version, author, changed in local time, from), and RENAME (refused names stay in the open box with the reason, focused), DUPLICATE (picks the copy), EXPORT .CITYSYS (published only, downloads under the server's file name) and DELETE (off for the running system; asks first).

The TTRPG_SYSTEM section gets a SYSTEMS.EXE button under the picker, passed only to the main admin (App's isPrimaryAdmin), and refetches the picker's list on SYSTEMS_CHANGED_EVENT, which the window sends after every change.

systemsLibrary.ts gains changedFact and SYSTEMS_CHANGED_EVENT.

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