feat(v5-M4): industrial formats + GPU acceleration + Python bindings

M4.1 — 工业格式 (Agent #0):
- JT parser: ISO 14306 Segment→Part→Mesh/LOD, XT B-Rep decode
- Parasolid XT: text/binary parser, Body→BrepModel mapping
- ACIS SAT: text format parser with version handling
- IFC: SPF parser, IfcWall/Slab/Beam/Column entities
- STEP AP242: PMI annotation + tolerance export
- 47 tests covering all formats + edge cases

M4.2 — GPU 加速 (Agent #1):
- CUDA kernels: mc_kernel, qem_cost_kernel, tri_intersect_kernel
- __constant__ memory for edge tables, atomic triangle collection
- CPU fallback when CUDA unavailable (seamless degradation)
- VDE_USE_CUDA CMake option, .cu compilation support
- 9 tests with CPU path validation

M4.3 — Python 绑定 (Agent #2):
- vde_brep: BrepModel, make_*, boolean, STEP/IGES, heal, validate
- vde_sdf: primitives, operations, to_mesh, gradient descent
- vde_cam: roughing/finishing/drilling, Tool, ToolLibrary
- vde_assembly: Assembly, AssemblyNode, interference, explode
- Version: 3.3.0 synced across pyproject/setup/__init__

13 files, ~5200 lines, 56+ tests

python/CMakeLists.txt

@@ -15,11 +15,14 @@ pybind11_add_module(_vde
     src/bind_core.cpp
     src/bind_curves.cpp
     src/bind_mesh.cpp
-    src/bind_sdf.cpp
+    src/vde_brep.cpp
+    src/vde_sdf.cpp
+    src/vde_cam.cpp
+    src/vde_assembly.cpp
 )
 
 target_include_directories(_vde
-    PRIVATE ${CMAKE_SOURCE_DIR}/include
+    PRIVATE ../include
 )
 
 target_link_libraries(_vde PRIVATE vde)