chore: remove obsolete files and directories from the repository

fix: ensure litellm is installed for LLM backend, .env never overrides HuggingFace secrets, add /ping endpoint

fix: CI smoke test — add tests/__init__.py, fix discovery pattern to test_*.py

feat(core): integrate core modules, update UI and docs

feat: universal chip support, claude theme, and SFT logging export

Tier-1 upgrade: fail-closed orchestration, CI, and benchmark export