Update /ok to serve dual health check/benchmarking role

benchmarks/bench_cpu_work.cpp

@@ -0,0 +1,34 @@
+#include <iostream>
+#include <nanobench.h>
+#include <string>
+
+#include "../src/cpu_work.hpp"
+
+int main(int argc, char *argv[]) {
+  int iterations = DEFAULT_HEALTH_CHECK_ITERATIONS; // Default: 7000
+
+  if (argc > 1) {
+    try {
+      iterations = std::stoi(argv[1]);
+      if (iterations < 0) {
+        std::cerr << "Error: iterations must be non-negative" << std::endl;
+        return 1;
+      }
+    } catch (const std::exception &e) {
+      std::cerr << "Error: invalid number '" << argv[1] << "'" << std::endl;
+      return 1;
+    }
+  }
+
+  std::cout << "Benchmarking spend_cpu_cycles with " << iterations
+            << " iterations" << std::endl;
+
+  ankerl::nanobench::Bench bench;
+  bench.minEpochIterations(10000);
+
+  // Benchmark the same CPU work that health checks use
+  bench.run("spend_cpu_cycles(" + std::to_string(iterations) + ")",
+            [&] { spend_cpu_cycles(iterations); });
+
+  return 0;
+}