wip(assembler): round L35 -- smooth passage walls without regular ribs (evaluator v21)

The shared passage carve took the minimum of piecewise-linear capsules (scallops at joins) and added
wall relief on regular 8 m / 4 m octaves, which read as evenly spaced ribs. Interior sweep joins are
now Catmull-Rom smoothed and the relief uses irregular rotated 43/29/19 m scales; the natural wobble
remains. New axial ripple audit (0.125 m radius samples, 0.5-8 m periods): beaded control and L34
geometry fail, all 24 passage rows pass. FI mouth tread apron tapered. 30/30 determinism, 16/16
invariants, ring audits LOD0-8 pass; cost within noise.

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

Standalone/Core/src/VoxelForgeFieldShared.h

@@ -331,6 +331,28 @@ VF_FIELD_INLINE float VF_FieldPerlin3D(float x,float y,float z)
     return VF_FieldPerlinLerp(y0,y1,sw);
 }
 
+VF_FIELD_INLINE float VF_FieldPassageWallRelief(float x,float y,float z,VF_FieldU32 seed)
+{
+    // Use long, non-commensurate rotated scales. The shared passage wall keeps broad,
+    // uneven rock relief without a short wavelength that can read as repeated rings.
+    const float broad=VF_FieldValueNoise(x+17.0f,y-23.0f,z+11.0f,43,
+        seed^0xB5297A4Du);
+    const float mid=VF_FieldValueNoise(y-7.0f,z+19.0f,x-31.0f,29,
+        seed^0x63D83595u);
+    const float fine=VF_FieldValueNoise(z+5.0f,x+29.0f,y-13.0f,19,
+        seed^0xA511E9B3u);
+    return 0.50f*broad+0.35f*mid+0.15f*fine;
+}
+
+VF_FIELD_INLINE float VF_FieldPassageGroundGrain(float x,float y,VF_FieldU32 seed)
+{
+    const float broad=VF_FieldValueNoise(x+3.25f,y-7.5f,0.0f,8,
+        seed^0xC2B2AE35u);
+    const float fine=VF_FieldValueNoise(y+11.75f,x-5.0f,0.0f,5,
+        seed^0x27D4EB2Fu);
+    return 0.65f*broad+0.35f*fine;
+}
+
 VF_FIELD_INLINE float VF_FieldOwnerFractal(float x,float y,float z,VF_FieldI32 octaves,
     VF_FieldI32 mode)
 {