Fast lookup of the cells making up a Program Area by reading
directly from the zone / zone_cell tables, avoiding the
terra::rasterize() cost paid by cells_in_polygon(). Returns
the same shape (cell_id, pct_covered) so downstream helpers
can consume it interchangeably; pct_covered is always 100
because zone_cell membership is binary.
Arguments
- con
a DBI connection (e.g. from
sdm_db_con())- pra_key
Program Area key (e.g. "CGM")