Dara's report from the Garden platform on Haven: every ray stopped on the
platform's 2 m rail at infinite height. The perimeter seal treated any wall
whose ink was not wholly inside the receiver's outer ring as the map edge,
and that rail touches the edge at one end, so its whole length was sealed.

The seal now asks for a quarter of a wall's ink to lie outside the ring.
Edge pieces straddle the ring at about half; interior strokes that graze it
sit below 3%, and the histogram is empty between. unseal_interior_walls.py
applies the same test to the bundled assets and restores 91 walls' bands
from before the seal, or from before the ray derivation where derivation had
emptied them, with bases anchored to the floor.

Gate: all tests pass.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>