Initial commit: rustytokens — native codebase indexer + MCP server

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/fixtures/cdemo/main.c

@@ -0,0 +1,5 @@
+#include "util.h"
+
+int main(void) {
+    return helper();
+}