research(render): retail capture cathedral-stair-arch — the #464 artifact pose (walk 5 frames + alphadepth 5 frames)

Root 0xF4180114 with seven outside views; retail admits the same seven
hall building-portal groups in the same order as acdream, yet shows the
solid far face above the arch. The fifth transcript pose for S4.

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

docs/research/2026-09-01-overhaul/oh-capture/README.md

@@ -12,6 +12,7 @@ capture is the detach frame and carries no events — never count it.
 | `holtburg-doorway-still` | interior `a9b4013f`, ov=2 | walk / parts / alphadepth |
 | `terrace-edge` | outdoor `f418000b` (14 buildings, identical to FW0) | walk / parts / alphadepth |
 | `foundry-deep` | interior `a9b40176`, ov=1 | walk / parts / alphadepth |
+| `cathedral-stair-arch` (#464 artifact pose, owner 2026-09-03 23:0x: `/teleloc F4180113 39.502899 19.832422 180.976700 1 0 0 0`, default distance tilted slightly up; retail eye `(39.58,16.99,182.79)`; retail screenshot in the #464 issue thread shows the solid far face above the arch) | interior `f4180114`, ov=7 | walk / alphadepth (no parts) |
 | `holtburg-doorway-still` #458 follow-up (2026-09-03 afternoon, a NEARBY pose — its own `P` line, not the walk capture's) | interior `a9b4013f`, ov=2 | `blockset` (every `Render::block_check` call of one frame: 2,601 blocks × 2 views + the return codes; `oh-capture-blockset.cdb.template`) / `blockcheck` (block `a9c9` only: the four corner interval vectors, z slab 75..330, ret 1 then 0; `oh-capture-blockcheck.cdb.template`) |
 
 `oh-recon.log` is the offset/breakpoint recon that PASSED before the poses.