chore: import upstream snapshot with attribution

rerun_cpp/tests/main.cpp

@@ -0,0 +1,11 @@
+#include <catch2/catch_session.hpp>
+#include <loguru.hpp>
+
+int main(int argc, char* argv[]) {
+    loguru::g_preamble_uptime = false;
+    loguru::g_preamble_thread = false;
+    loguru::init(argc, argv); // installs signal handlers
+
+    int result = Catch::Session().run(argc, argv);
+    return result;
+}