wip(l59): open helix shaft (ledge open to the core) -- PARKED: jagged inner ramp edge, audit ROI missed it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

ARCHITECTURE.md

@@ -2265,32 +2265,36 @@ mouth and off the walk route. It stays disabled by default. Active records carry
 L43's report records the off/on hashes, walk and interface audits, outside-stamp timing, tier
 results, captures and any failed runs.
 
-### 8.54 Opt-in native lattice field — World Assembler M3 R26 slice 1 (Linux L58)
+### 8.54 Opt-in native lattice field — World Assembler M3 R26 slices 1–2 (Linux L58–L59)
 
-`Core.Lattice.PrimitiveField` is a version-1 recipe selected only for one Maze or VerticalShafts
+`Core.Lattice.PrimitiveField` is an opt-in recipe selected only for one Maze or VerticalShafts
 strate by `--recipe=lattice --lattice-strate=N`. The legacy generator assets and their default
-dispatch stay unchanged. Planning first binds the actual incoming lower mouth and outgoing upper
-mouth from the resolved passage records, then creates arrival/exit overlap corridors, a mandatory
-four-turn helix and the maze spine; two deterministic dead ends are added after that route. The
-resolved room and edge seeds use `(world seed, strate, recipe version, stable ID)`. An audit control
-translates the helix 20 m away from both route junctions to make the shaft network orphaned.
+dispatch stay unchanged. Version 2 binds the actual incoming lower mouth and outgoing upper mouth,
+then creates arrival/exit overlap corridors, an open vertical shaft and the maze spine; two
+deterministic dead ends are added after that route. Resolved room and edge seeds use
+`(world seed, strate, recipe version, stable ID)`. The orphan control translates the shaft 20 m
+away from both route junctions and must fail reachability.
 
-The prototype helix uses a 6 m centreline radius, 3 m clear width, 5 m pitch, four turns and 2.6 m
-finished floor-to-soffit height. Its centreline descends 20 m over roughly 151 m; the inner-edge
-grade is about 10.0 degrees. The 2.4 m floor-wall smooth-max gives an isolated ideal fillet radius
-of 0.8485 m. A separate 0.4 m feature-union blend prevents adjoining ramps from erasing the tread.
-The swept-clear diameter is 15 m; the conservative padded feature envelope is about 20.6 m (the
-approved approximately 21 m site envelope).
+The version-2 shaft core is a vertical cylinder of 4.5 m radius. Its air continues 8 m above the
+top tread and 2 m below the bottom tread. The ramp winds around the core at a 6 m centreline radius,
+with 3 m clear width, 5 m pitch and four turns. The open annular shaft air joins the core air, while
+one-metre support slabs follow the helix under each tread. This leaves a 4 m vertical gap between
+one tread and the underside of the next. The ledge's inner edge is open to the well; the route
+centreline stays 1.5 m from the drop and leaves 1.16 m beyond the 0.34 m capsule radius. Its inner
+edge grade is about 10.0 degrees. The maze retains 2.6 m room headroom. The shaft's padded outer
+design envelope is 21 m. The 1.9 m floor-wall smooth-max gives an isolated ideal fillet radius of
+0.6718 m; the separate 0.05 m feature-union blend keeps route junctions connected.
 
 The layout reuses the resolved cavern graph vocabulary. A per-strate opt-in selects the native
-negative-solid/positive-air field; canonical feature order is stable-ID order. Room/corridor bounds
-are indexed by the graph BVH and polyline segments have a nested deterministic BVH for density and
-interval queries. Box classification stays conservative, and `isTileShapeFree` refuses any tile
-that intersects the graph. The L58 pipeline audits the composed field from actual mouth to mouth
-with a 0.34 m by 1.76 m capsule, per-station support, 2.2 m clearance and a 15 degree grade limit;
-it also checks the orphan control, brute-force interval samples and the composed wall-foot fillet.
-The Linux58 report contains the measured reachability, surface, peer-determinism, timing and capture
-results; the code path is not promoted to legacy Maze/VerticalShafts generation.
+negative-solid/positive-air field; canonical feature order is stable-ID order. The ring-shaped shaft
+air and its support layers use an analytic helix lookup instead of testing every polyline segment
+per density sample. The core cylinder and annular wall have conservative interval bounds; false
+all-air and all-solid controls remain rejected, and `isTileShapeFree` refuses occupied tiles. The
+L59 pipeline checks the composed field from actual mouth to mouth with a 0.34 m by 1.76 m capsule,
+support at every station, 2.2 m clearance and a 15 degree grade limit. It also checks the orphan
+control, whole-surface ramp lip/wall-foot/underside, brute-force interval samples and the composed
+wall-foot fillet. See the Linux58 and Linux59 reports for evidence. This code path is not promoted
+to legacy Maze/VerticalShafts generation.
 
 ## 9. Multiplayer model (listen-server first, dedicated-friendly)