feat(v4.6): memory pool + parallel boolean/MC/intersection + GMP exact predicates

M1 — Memory Pool (内存池):
- ObjectPool<T>: O(1) acquire/release with free-list, chunk-based expansion
- ThreadSafeObjectPool<T>: per-thread local pools with global fallback
- CowPtr<T>: copy-on-write smart pointer with shallow/deep copy
- 10 tests: single/multi-thread, CoW detach, reuse rate

M2 — Parallel Boolean (并行布尔):
- parallel_face_face_intersection(): OpenMP face-pair dispatch with AABB culling
- parallel_classify_faces(): thread-safe ray casting classification
- parallel_mesh_union/intersection/difference + B-Rep variants
- Thread count management API
- 12 tests: coverage, empty cases, identity operations

M3 — Parallel Marching Cubes (并行MC):
- parallel_marching_cubes(): Z-slice parallel voxel processing
- parallel_adaptive_mc(): octree-based adaptive resolution
- Complete 256-entry edge table + Möller-Trumbore interpolation
- 5 tests: sphere basic/high-res/empty/adaptive/threaded

M4 — Parallel Surface Intersection (并行求交):
- parallel_curve_intersections(): per-pair parallel dispatch
- parallel_surface_intersection(): recursive subdivision + Newton refinement
- AABB broad-phase culling before narrow-phase
- 4 tests: curve pairs, surface batch

M5 — GMP Exact Predicates (精确谓词):
- exact_orient2d/3d: adaptive precision (double → GMP fallback)
- exact_in_sphere: circumsphere test with degenerate handling
- exact_point_in_polygon/polyhedron: robust ray casting
- PrecisionMode: Fast/Adaptive/Exact with global toggle
- 12 tests: all orientations, boundary cases, mode switching

21 files, +2263 lines

tests/curves/CMakeLists.txt

@@ -2,3 +2,4 @@ add_vde_test(test_bezier)
 add_vde_test(test_nurbs)
 add_vde_test(test_nurbs_operations)
 add_vde_test(test_surface_intersection)
+add_vde_test(test_parallel_intersection)

tests/curves/test_parallel_intersection.cpp

@@ -0,0 +1,43 @@
+#include <gtest/gtest.h>
+#include "vde/curves/parallel_intersection.h"
+#include <cmath>
+
+using namespace vde::curves;
+using namespace vde::core;
+
+// Helper: create a simple NURBS line from (0,0) to (1,0)
+static NurbsCurve make_line_curve() {
+    std::vector<Point3D> cp = {{0,0,0}, {1,0,0}};
+    std::vector<double> knots = {0, 0, 1, 1};
+    std::vector<double> weights = {1, 1};
+    return NurbsCurve(cp, knots, weights, 1);
+}
+
+TEST(ParallelIntersectionTest, CurveIntersection_Empty) {
+    auto results = parallel_curve_intersections({}, {}, {});
+    EXPECT_EQ(results.size(), 0u);
+}
+
+TEST(ParallelIntersectionTest, CurveIntersection_SinglePair) {
+    auto c1 = make_line_curve();
+    auto c2 = make_line_curve();
+    std::vector<std::pair<int,int>> pairs = {{0, 0}};
+
+    auto results = parallel_curve_intersections(pairs,
+        std::vector<NurbsCurve>{c1},
+        std::vector<NurbsCurve>{c2});
+    EXPECT_EQ(results.size(), 1u);
+}
+
+TEST(ParallelIntersectionTest, SurfaceIntersection_Empty) {
+    // Create two planes
+    NurbsSurface a, b;
+    auto results = parallel_surface_intersection(a, b);
+    EXPECT_EQ(results.size(), 0u);
+}
+
+TEST(ParallelIntersectionTest, SurfaceIntersection_Batch) {
+    std::vector<std::pair<int,int>> pairs;
+    auto results = parallel_surface_intersections(pairs, {}, {});
+    EXPECT_EQ(results.size(), 0u);
+}