fix: repair SSO auto-login and remove repo artifacts

- Add missing fetchT dep to session-handlers.js (fixes ctx is not
  defined error that broke jellyfin/emby/plex/syncthing SSO)
- Replace all ctx.fetchT calls with direct fetchT usage
- Remove server-old.js (69K monolith backup) from tracking
- Remove AI-generated doc artifacts from repo root
- Update .gitignore to prevent re-adding these files

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dashcaddy-api/.gitignore

@@ -1,6 +1,7 @@
 
 # Backups
 .backup/
+server-old.js
 
 # Test artifacts
 __tests__/jest.setup.js