Fill hierarchy columns down to each row's real depth

Stamp each row with its real admin depth, then cascade every admin-hierarchy column down to that depth, run against an already-clipped/stitched layer (an edge-match/edge-mosaic output). A layer missing an ancestor level's columns entirely needs schema-join against that parent layer first, since schema-fill only cascades values already on the row.

topo-tools schema-fill admin4.parquet --name-field state_name --code-field state_code

This stamps a new adm_lvl column (rename it with --depth-column) and fills every level's name/code columns down to that depth, per row, so a genuine NULL at a row's own real depth stays NULL rather than being backfilled from a shallower ancestor. Level columns are auto-detected structurally when --name-field/--code-field are omitted.

Run package-polygons afterward to dissolve every level normally; it carries the stamped depth column through automatically.

See schema-fill reference and its explanation page for the pinned-fill rule in detail.