feat(v3.2): CI/CD config + Python bindings setup

- Add .gitea/workflows/build.yml (build, test, docs, python binding CI)
- Add root pyproject.toml + setup.py (CMake-based pip install)
- Add root vde/__init__.py (Python package entry point)
- Update README: CI badge, version 3.2.0, Python install instructions
- Bump project version to 3.2.0 across CMakeLists.txt, python/setup.py, python/vde/__init__.py
- Add build_py/ to .gitignore

vde/__init__.py

@@ -0,0 +1,24 @@
+"""
+ViewDesignEngine — High-performance C++ CAD geometry engine for Python.
+
+Submodules:
+    vde.core     — Point3D, Vector3D, AABB3D, Polygon2D, convex hull, distance, transforms
+    vde.curves   — BezierCurve, BSplineCurve, NurbsCurve
+    vde.mesh     — delaunay_2d, delaunay_3d, HalfedgeMesh
+    vde.sdf      — SdfNode, CSG tree, marching cubes mesh conversion
+    vde.sketch   — 2D sketch constraint solver
+    vde.boolean  — 2D/3D boolean operations
+    vde.collision — GJK/EPA collision detection
+    vde.brep     — B-Rep topology modeling
+"""
+
+__version__ = "3.2.0"
+
+# Native module (_vde) is built via CMake and copied here at install time.
+# Fallback: try importing so IDEs/tools can inspect.
+try:
+    from ._vde import core, curves, mesh, sdf
+except ImportError:
+    pass  # native module not yet built; pip install will build it
+
+__all__ = ["core", "curves", "mesh", "sdf"]