feat: cog_geographic_rollup
Wraps cog_spending across a named list of state/county/city layers, tagging each row with its `layer` and attaching a scope_note that documents geographic-scope caveats (state totals are statewide, county totals include areas outside a listed city, city proper excludes special districts). Per-capita uses each layer's own population from the canonical_fips_xwalk. Provenance is inherited from cog_spending but rewritten to reflect the outer verb (verb, call, layers). Tests: 19 new / 99 total pass. devtools::check() 0E/0W/2N.
This commit is contained in: