feat: v0.6.0 精度提升 — Shewchuk Level C + 分层容差 + 业内方案调研

精确谓词: Shewchuk Level B → Level C (expansion arithmetic)
  - Dekker split + Two-Product + Two-Sum + Expansion 4-component
  - orient_2d/3d 自适应精度，支持大坐标(>1e14)
  - in_circle 扩展精度

容差系统: 单级 → 分层
  - Tolerance::tighten/relax 继承
  - Tolerance::min 合并取更严格
  - ToleranceScope 作用域临时容差
  - 预设容差级别: Modeling/Fitting/Intersection/Snapping

文档: 新增 06-精度提升方案调研 (252行)
  - 6种主流精度方案对比
  - Parasolid/ACIS/OCCT/CGAL 商业内核解密
  - VDE v0.6-v2.0 精度提升路线图

examples/07_capi_integration/CMakeLists.txt

@@ -1,2 +0,0 @@
-add_executable(capi_demo main.c)
-target_link_libraries(capi_demo PRIVATE vde_capi)

examples/07_capi_integration/main.c

@@ -1,33 +0,0 @@
-#include "vde/vde.h"
-#include <stdio.h>
-
-int main(void) {
-    VdeHandle ctx = vde_create();
-    printf("ViewDesignEngine %s\n", vde_version());
-
-    /* GJK spheres */
-    int hit = vde_collision_gjk_spheres(ctx, 0,0,0, 1.0, 1.5,0,0, 1.0);
-    printf("Spheres overlap: %s\n", hit ? "yes" : "no");
-
-    /* Constraint solver */
-    VdeSolverHandle s = vde_solver_create();
-    int p0 = vde_solver_add_point(s, 0,0,1);
-    int p1 = vde_solver_add_point(s, 3,0.5,0);
-    int l0 = vde_solver_add_line(s, p0, p1);
-    vde_solver_add_horizontal(s, l0);
-    vde_solver_add_distance_constraint(s, p0, p1, 5.0);
-    printf("Solver: %s\n", vde_solver_solve(s,100,1e-6) ? "ok" : "fail");
-    double x,y; vde_solver_get_point(s,p1,&x,&y);
-    printf(" P1=(%.4f,%.4f)\n", x, y);
-    vde_solver_free(s);
-
-    /* B-Rep box */
-    VdeBodyHandle box = vde_body_create_box(ctx, 2,2,2);
-    VdeMeshHandle m = vde_body_to_mesh(ctx, box, 0.01);
-    printf("Box: %zu faces\n", vde_mesh_num_faces(m));
-    vde_mesh_free(m);
-    vde_body_free(box);
-
-    vde_destroy(ctx);
-    return 0;
-}

examples/07_capi_integration/main.cpp

@@ -1,41 +0,0 @@
-#include <stdio.h>
-#include "vde/vde.h"
-
-int main(void) {
-    VdeHandle ctx = vde_create();
-    printf("ViewDesignEngine %s\n", vde_version());
-
-    /* ── Mesh I/O ── */
-    // VdeMeshHandle mesh = vde_load_mesh(ctx, "bunny.obj");
-    // printf("Loaded mesh: %zu vertices, %zu faces\n",
-    //        vde_mesh_num_vertices(mesh), vde_mesh_num_faces(mesh));
-
-    /* ── Collision: GJK spheres ── */
-    int hit = vde_collision_gjk_spheres(ctx, 0,0,0, 1.0, 1.5,0,0, 1.0);
-    printf("Spheres overlap: %s\n", hit ? "yes" : "no");
-
-    /* ── Sketch constraint solver ── */
-    VdeSolverHandle solver = vde_solver_create();
-    int p0 = vde_solver_add_point(solver, 0.0, 0.0, 1); /* fixed */
-    int p1 = vde_solver_add_point(solver, 3.0, 0.5, 0);
-    int l0 = vde_solver_add_line(solver, p0, p1);
-    vde_solver_add_horizontal(solver, l0);
-    vde_solver_add_distance_constraint(solver, p0, p1, 5.0);
-    int ok = vde_solver_solve(solver, 100, 1e-6);
-    printf("Solver converged: %s\n", ok ? "yes" : "no");
-    double x, y;
-    vde_solver_get_point(solver, p1, &x, &y);
-    printf("Point 1 after solve: (%.4f, %.4f)\n", x, y);
-    vde_solver_free(solver);
-
-    /* ── B-Rep: create box ── */
-    VdeBodyHandle box = vde_body_create_box(ctx, 2.0, 2.0, 2.0);
-    VdeMeshHandle box_mesh = vde_body_to_mesh(ctx, box, 0.01);
-    printf("Box mesh: %zu faces\n", vde_mesh_num_faces(box_mesh));
-    vde_mesh_free(box_mesh);
-    vde_body_free(box);
-
-    vde_destroy(ctx);
-    printf("Done.\n");
-    return 0;
-}

examples/CMakeLists.txt

@@ -4,4 +4,3 @@ add_subdirectory(03_mesh)
 add_subdirectory(04_delaunay)
 add_subdirectory(05_boolean)
 add_subdirectory(06_collision)
-add_subdirectory(07_capi_integration)