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All 594 records now have identical 17-column schema with catalog URLs

Added catalog URLs for all 3 sources: pw_url, tripsit_url, erowid_url

Delete files psychonaut_tripsit_erowid_xref.jsonl with huggingface_hub

Delete files pw_erowid_crossref.jsonl with huggingface_hub

Unified cross-reference: ALL records use the same schema (17 columns)

594 records: 3-way mapping PW ↔ TripSit ↔ Erowid

117 substances cross-referenced between PW and Erowid

initial commit