_SECTION_NUMBER_RE only had patterns for §/Art/Section/Kapitel/Annex
but missed NIST-style identifiers (AC-1, GV.OC-01, 3.1, A01:2021).
This caused 0% section rate for all NIST/BSI/ENISA documents even
though sections were correctly detected — the section NUMBER wasn't
extracted from the header.
Also adds:
- reupload_legal_strategy.py: re-upload with legal chunking
- extract_and_upload_nist.py: local PDF extraction workaround
- qdrant-snapshot.sh: backup mechanism for Qdrant collections
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>