feat: Python 绑定 — pybind11 核心/曲线/网格模块

- 使用 pybind11 v2.11.1 (FetchContent) 构建 _vde 原生模块
- 模块化结构: bind_core.cpp / bind_curves.cpp / bind_mesh.cpp
- 暴露核心类型: Point2D, Point3D, Vector3D, AABB3D, Polygon2D
- 暴露曲线: BezierCurve, BSplineCurve, NurbsCurve
- 暴露网格: delaunay_2d/3d, DelaunayResult, HalfedgeMesh
- 变换函数: translate, rotate, scale 等
- Python 包 vde/ 含 __init__.py 及子模块封装
- setup.py 支持 pip install -e . 可编辑安装
- VDE_BUILD_PYTHON CMake 选项 (默认 OFF)，通过 -DVDE_BUILD_PYTHON=ON 启用

python/setup.py

@@ -0,0 +1,69 @@
+"""
+ViewDesignEngine — CAD computational geometry engine.
+
+Build and install:
+    pip install -e .          # editable install
+    pip install .             # regular install
+
+Requires:
+    - CMake >= 3.16
+    - C++17 compiler
+    - Eigen3 (auto-fetched if not found)
+"""
+from setuptools import setup, find_packages
+from pybind11.setup_helpers import Pybind11Extension, build_ext
+
+import sys
+from pathlib import Path
+
+# ── Configure the native extension ──────────────────
+ext_modules = [
+    Pybind11Extension(
+        "vde._vde",
+        sorted([
+            "src/bind_module.cpp",
+            "src/bind_core.cpp",
+            "src/bind_curves.cpp",
+            "src/bind_mesh.cpp",
+        ]),
+        include_dirs=[
+            "../include",                # vde headers
+        ],
+        extra_compile_args=["-std=c++17"],
+        # Propagate Eigen3 (set up via CMake or system path)
+        cxx_std=17,
+    ),
+]
+
+setup(
+    name="vde",
+    version="1.0.0",
+    author="ViewDesignEngine Contributors",
+    description="CAD computational geometry engine",
+    long_description=Path(__file__).parent.joinpath("..", "README.md").read_text(
+        encoding="utf-8"
+    ) if Path(__file__).parent.joinpath("..", "README.md").exists() else "",
+    long_description_content_type="text/markdown",
+    url="https://github.com/ViewDesignEngine/ViewDesignEngine",
+    packages=find_packages(),
+    ext_modules=ext_modules,
+    cmdclass={"build_ext": build_ext},
+    python_requires=">=3.8",
+    install_requires=[
+        "pybind11>=2.11.0",
+    ],
+    classifiers=[
+        "Development Status :: 4 - Beta",
+        "Intended Audience :: Science/Research",
+        "License :: OSI Approved :: MIT License",
+        "Programming Language :: C++",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
+        "Topic :: Scientific/Engineering",
+    ],
+    zip_safe=False,
+)