stabilize: pin deps, limit BLAS threads, proper HF cache

build(docker): add Dockerfile and boot entrypoint for HF Spaces

Spaces: docker SDK + clean README

Clean Dockerfile; pre-translate paragraphs; add /debug/translate

Clean Dockerfile; pre-translate contexts to EN before summarizing

Bust cache to reinstall deps

Fix HF Spaces cache permissions and set model cache

Add app_file and root app.py for HF Space