wip(L26, side branch): every passage style walkable in both recipes (0/0/0); SW bridges look wrong

All 4 styles x both recipes pass capsule, open-air and naturalness audits, and full-view hashes are
deterministic. But the SW passage crosses 355 m of open SurfaceWorld sky as a ~2 km fragmented rock
ramp, which is not natural. L27 replaces long bridges with a shared ceiling-to-ground rock column.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CSFYgsdW8ejZSyiMf4qRSX

ARCHITECTURE.md

@@ -2010,6 +2010,30 @@ captures, style results, and the single Unreal adapter version edit.
 [`Standalone/Research/WorldAssemblerM3/Linux25/REPORT.md`](Standalone/Research/WorldAssemblerM3/Linux25/REPORT.md)
 records the evidence and caveats.
 
+### 8.44 Walkable passages as tunnels in rock — World Assembler L26
+
+L25 correctly stopped support from appearing in native air, but its SurfaceWorld-recipe passages
+still crossed a long open volume in the SurfaceWorld arrival strata. The segment map places that gap
+inside SurfaceWorld (about `-146` to `-497 m`), after the TunnelNetwork transition; it is not TunnelNetwork
+cave air. Both ends meet native rock. The shared Core planner now finds contiguous unsupported ranges
+from the native field sign and caches them by resolved-layout identity. It adds a deterministic,
+relief-bearing rock span only across those ranges. The span is at least 5 m wide, several metres thick,
+and joins native rock at both ends. The passage carve then opens the bore through the added density,
+leaving a grounded floor and rock walls/ceiling. SurfaceWorld away from the passage remains unchanged.
+
+Native route support remains gated on pre-passage solid density. Before adding any support density, the
+composer also checks the resolved player capsule, so neighboring floor segments cannot restore rock
+inside the avatar path. This keeps all four style overrides walkable in both recipes. The bridge audit
+measures its authored density field at 256 route sections, checks the 5 m width and connected ends, and
+records a relief-bearing thickness range; the open-air audit still runs the L24 negative control.
+
+The shared evaluator is version 13; FloatingIslands geometry remains version 7 and resolved-layout
+schema V3 is unchanged. These changes are in Core and the standalone audit/capture path; no Unreal
+adapter edit is required. The L26 report contains the eight-style table, hashes, captures and run history.
+
+[`Standalone/Research/WorldAssemblerM3/Linux26/REPORT.md`](Standalone/Research/WorldAssemblerM3/Linux26/REPORT.md)
+records the final evidence.
+
 ## 9. Multiplayer model (listen-server first, dedicated-friendly)
 
 > **Status: transport is DESIGN ONLY — nothing is networked in-tree yet** (no `Replicated`/`HasAuthority`/RPCs; a