Native detz entry + libcurl HTTP/SSE client; drop python execvp shim

taicpp/main.cpp

@@ -1,2 +1,10 @@
-#include "src/cli/cli.h"
-int main(int argc, char** argv) { return detz::cli::DetzCli{}.run(argc, argv); }
+#include "cli/cli.h"
+#include "version.hpp"
+#include <cstdio>
+#include <string>
+int main(int argc, char** argv){
+  detz::cli::Parser p; auto cmd = p.parse(argc, argv);
+  if(cmd.opts.version){ std::puts(std::string(detz::kVersion).c_str()); return 0; }
+  if(cmd.opts.cap_manifest){ std::fputs("# tai CAP agent manifest\n", stdout); return 0; }
+  return cmd.run();
+}