fix: grid lines for split ruling edges only in display and export meshes; record the moved seeds (#961)

#921's grid lines through the vertices that split a ruling edge also went into the meshes Boolean operations intersect, which changed seven robustness seeds (seed 2's sphere cut failed). Deflection::rulings now asks for them only in the kernel's own tessellation (display, export, measurement). The seeds #936 (rejected instead of unsupported), #946 (26 and 85 build, others fail differently) and #921's display side (about 1e-6) moved are recorded with their reasons.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

vendor/truck-meshalgo/src/tessellation/mod.rs

@@ -64,6 +64,10 @@ pub struct Deflection {
     pub angle: f64,
     /// Sag below which `angle` no longer splits a facet.
     pub floor: f64,
+    /// SolidCraft: grid lines through the vertices that split a face's ruling edges (see
+    /// `with_ruling_vertices`). Meshes for display and export ask for them; the meshes Boolean
+    /// operations intersect do not, so a Boolean's result does not depend on them.
+    pub rulings: bool,
 }
 
 impl Deflection {
@@ -83,6 +87,7 @@ impl Deflection {
             chord: tol,
             angle: f64::INFINITY,
             floor: 0.0,
+            rulings: false,
         }
     }
 
@@ -95,7 +100,7 @@ impl Deflection {
         let angle = self.angle * f64::from(1u32 << level.min(Self::MAX_RELAX));
         match level == 0 || (level < Self::MAX_RELAX && angle < std::f64::consts::PI) {
             true => Self { angle, ..*self },
-            false => Self::chord(self.chord),
+            false => Self { rulings: self.rulings, ..Self::chord(self.chord) },
         }
     }
 

vendor/truck-meshalgo/src/tessellation/triangulation.rs

@@ -789,8 +789,8 @@ fn insert_surface(
         let (u, v) = bounded_surface_division(&surface, range, tol, cap);
         let (u_ruled, v_ruled) = (u.len() <= 3, v.len() <= 3);
         let (u, v) = balanced_grid(&surface, u, v, cap);
-        let v = with_ruling_vertices(v, polyline, 1, v_ruled, u.len(), cap);
-        let u = with_ruling_vertices(u, polyline, 0, u_ruled, v.len(), cap);
+        let v = with_ruling_vertices(v, polyline, 1, tol.rulings && v_ruled, u.len(), cap);
+        let u = with_ruling_vertices(u, polyline, 0, tol.rulings && u_ruled, v.len(), cap);
         (u, v)
     };
     let insert_res: Vec<Vec<Option<_>>> = udiv