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

tests/dynamic_fixtures/cpp/libfuzzer/vuln.cpp

@@ -0,0 +1,17 @@
+// Phase 16 — libFuzzer entry, vulnerable. Cap: CODE_EXEC.
+
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <string>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+    std::printf("__NYX_SINK_HIT__\n");
+    std::fflush(stdout);
+    if (size == 0 || size > 2048) return 0;
+    std::string payload(reinterpret_cast<const char*>(data), size);
+    std::string cmd = std::string("echo hello ") + payload;
+    std::system(cmd.c_str());
+    return 0;
+}