docs(render): cathedral-leak pose — owner's retail screenshot described beside the transcript

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

docs/research/2026-09-01-overhaul/s3-walk-ownership-map.md

@@ -145,8 +145,14 @@ Lead verifies every finding against the source before an edit (S2 precedent:
   `ov=4`, EC/OC stamps, 531 `LC`/`SC` land-cell draws per frame in far-to-near
   order over landblocks `f3`–`fe` × `00`–`18`), `cathedral-leak.parts.log`
   (3 frames, 5,933 PD / 965 DM), `cathedral-leak.alphadepth.log` (5 frames,
-  1,407 AM / 2,856 FL / 28 PM / 16 PC). This pose is S3/S4's primary oracle:
-  the target is to reproduce retail's frame at it, leak included.
+  1,407 AM / 2,856 FL / 28 PM / 16 PC). Owner's retail screenshot (2026-09-03, 2013 client, to be saved as
+  `logs/oh-capture/cathedral-leak.retail.png`): standing on the floating
+  stairs in `f4180108`, a large slab of the EXTERIOR wall (arched exterior
+  stone texture) cuts diagonally through the stair chamber from the upper
+  left, drawn over the interior landings and ramps that remain visible around
+  it — the same leak acdream shows at the same spot. This pose is S3/S4's
+  primary oracle: the target is to reproduce retail's frame at it, leak
+  included.
 - Remaining poses per the kit README: `cathedral-arrival`, `holtburg-doorway-still`,
   `terrace-edge`, `foundry-deep`.