fix: Delaunay3D circumcenter 完整实现 + 测试恢复

bench/bench_main.cpp

@@ -0,0 +1,11 @@
+/// bench_main.cpp — Google Benchmark entry point
+/// Usage:
+///   ./vde_bench          — run all registered benchmarks
+///   ./vde_bench_bvh      — BVH benchmarks only
+///   ./vde_bench_delaunay --benchmark_min_time=0.05
+///
+/// Each benchmark executable is self-contained (links its own main).
+
+#include <benchmark/benchmark.h>
+
+BENCHMARK_MAIN();