[pitboss] phase 16: Track B — Rust + C + C++ harness emitter shapes

tests/dynamic_fixtures/cpp/main_argv/benign.cpp

@@ -0,0 +1,13 @@
+// Phase 16 — main(argc, argv), benign.
+// Shape marker: int main(int argc, char *argv[])
+
+#include <cstdio>
+#include <cstdlib>
+
+int nyx_entry_main(int argc, char *argv[]) {
+    (void)argc; (void)argv;
+    std::printf("__NYX_SINK_HIT__\n");
+    std::fflush(stdout);
+    std::system("echo hello");
+    return 0;
+}