- /admin/api/system-stats now built on the front (psutil for CPU/RAM, torch-free
  gpu_detect for GPU/VRAM) instead of poll-proxying to the GIL-busy engine, so the
  Tasks header tiles stay live during generation.
- Removed from codai/admin/routes.py (engine), now all owned by the front: the
  dead page-GET routes (login/admin/models/tokens/users/tasks/chat/settings/
  archive/change-password GET — the front renders these), api_gpu_stats and
  api_system_stats. Kept the auth POSTs (login/logout/change-password), _tmpl,
  _do_task_cancel, build_settings_dict and api_save_settings.

Verified: front _build_system_stats returns cpu/ram/gpu/vram; routes.py imports.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011DDv7BchtZQWsnPG6Jm49m