Impact region to GADM 4.1 administrative unit aggregation weights

Weights for aggregating Climate Impact Lab impact region results to GADM 4.1 administrative units, at ADM1 (state or province) and ADM2 (district) level, keyed by GADM's GID codes. Each level comes in two directions, and the choice matters. The per_source files split a region's total between the units it touches (shares sum to one per region); use them for totals like dollars or deaths. The per_destination files average over the regions inside each unit (shares sum to one per unit); use them for averages like rates or temperatures. One direction cannot do the other's job. A sibling record covers GADM 2.0; the two versions have different unit universes and keys and are not comparable. Each artifact is a parquet table plus a manifest carrying provenance and a SHA256 checksum of the parquet. Source geometry: world-combo-201710, 24,378 impact regions. Target: GADM 4.1, version label gadm-4.10-impactmap-copy-2022, population weights from GPW v4r10 (2015). With the cil_regionalization package (Climate Impact Lab GitHub organisation): fetch_weights("gadm41-adm1-per-source"), and likewise for the other three names.