The previous attempt at this publish (b7fea73, reverted as bb160bc) broke the
live map: resolveAssetsBase computed <treeRoot>/../assets, one segment too high,
so boundary geojson 404'd and the map painted a basemap with none of our data.
Fixed at source in 852310d0 -- the asset pool lives INSIDE the tree, which is
what a leaf's own '../../assets' has always meant and what generate-tree stages.
Now covered by check:embed-base, pure path arithmetic, mutation-tested against
the exact off-by-one.
Verified before push: 24 bundles, 22 manifest bundles all resolving, 57 leaves
with zero unresolved script srcs, boundaries present at the path the fix
targets, tree settled, diff scoped to app/doxa-maps only.
63cea35291