Add Factorio World Management feature to GSM

- Add gsm-frontend to repository (React + Vite + TailwindCSS)
- New "Worlds" tab for Factorio server with:
  - List saved worlds with Start/Delete actions
  - Create new world with full map generation parameters
  - Preset selection (Default, Rich Resources, Rail World, etc.)
  - Save custom configurations as templates
- Show which save will be loaded in Overview tab
- Lock world management while server is running
- Backend changes deployed to server separately

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

@@ -1 +1,6 @@
-gsm-frontend/
+node_modules/
+dist/
+*.tar.gz
+.env
+.env.*
+!.env.example