Boundary polygons not reprojected

Uploaded boundary polygons should be reprojected to the projection of the `geom` column before insertion.

Start by locating the upload insertion path and the `geom` column definition, then trace how boundary polygon coordinate reference systems are handled before insertion. Confirm the target projection and add coverage for a polygon whose source projection differs; done means the stored geometry uses the `geom` column's projection.

Written by the indexing model from the issue text.