data(custodian): resolve 57 PENDING files to proper GHCID locations
Resolved NL-XX-XXX-PENDING files to proper regional GHCIDs:
- 57 new files with proper location codes (city, region)
- Cities include: Amsterdam, Rotterdam, Utrecht, Leiden, Groningen, etc.
- 34 original PENDING files archived to archive/pending_duplicates_20250109/
Examples:
- NL-XX-XXX-PENDING-AMSTERDAM-MUSEUM → NL-NH-AMS-M-AM (Amsterdam Museum)
- NL-XX-XXX-PENDING-GRONINGEN-MUSEUM → NL-GR-GRO-M-GM (Groninger Museum)
- NL-XX-XXX-PENDING-KUNSTHAL-ROTTERDAM → NL-ZH-ROT-G-KR (Kunsthal Rotterdam)
