core: one tunnel for two strates with landing chambers (L151, owner design; v238, grade open)

Each passage records upper and lower landing chambers (floor, gradient, radius, 4.5 m clear height) composed with the
tunnel shell; cave route endpoints bind to the chambers; envelope audit permits only the named chamber joints.
Seed 2: 0 solid in 319,579 passage+chamber capsule samples, 0 shell violations, 0 envelope conflicts, controls fire.
Open: tunnel-to-chamber floor blend leaves 19.1/19.0 deg grades (limit 15); sweeps/timing not run.

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

Standalone/Research/WorldAssemblerM3/Linux151/captures/INDEX.md

@@ -0,0 +1,35 @@
+# L151 matched owner tunnel landing captures
+
+Seed 0 camera poses resolved from the L151 owner layout and reused for both versions. Each view is at eye height at one of the three tunnel landing chambers. Before uses the L150 head build; after uses L151 source stamp `1ca3b84f6d35f7f355ec0f72dabd3b87a455ea02e5789fea611916962e5db8e5`.
+
+## passage/0-1/0 / upper landing
+
+- Before: [image](before-l150-0-1-0-upper-landing.jpg)
+- After: [image](after-l151-0-1-0-upper-landing.jpg)
+
+## passage/0-1/0 / lower landing
+
+- Before: [image](before-l150-0-1-0-lower-landing.jpg)
+- After: [image](after-l151-0-1-0-lower-landing.jpg)
+
+## passage/1-2/0 / upper landing
+
+- Before: [image](before-l150-1-2-0-upper-landing.jpg)
+- After: [image](after-l151-1-2-0-upper-landing.jpg)
+
+## passage/1-2/0 / lower landing
+
+- Before: [image](before-l150-1-2-0-lower-landing.jpg)
+- After: [image](after-l151-1-2-0-lower-landing.jpg)
+
+## passage/2-3/0 / upper landing
+
+- Before: [image](before-l150-2-3-0-upper-landing.jpg)
+- After: [image](after-l151-2-3-0-upper-landing.jpg)
+
+## passage/2-3/0 / lower landing
+
+- Before: [image](before-l150-2-3-0-lower-landing.jpg)
+- After: [image](after-l151-2-3-0-lower-landing.jpg)
+
+Capture quality failures: 0/12.