Merge data from PENDING files (with XX-XXX placeholders) into their
corresponding enriched custodian records with proper GHCIDs.
Countries affected:
- DE: 4 institutions (Deutsche Stiftung, Jewish Museum Berlin, etc.)
- ES: 1 institution (Biblioteca Nacional de España)
- FR: 1 institution (NMO)
- ID: 18 Indonesian museums and archives
- NL: 111 Dutch institutions across all provinces
- US: 1 institution (ARCA)
The PENDING files are deleted after merge; originals archived in
data/custodian/archive/pending_merged_20250109/
bd06e4f864