Function roq_file_exists

tests/test_mcp.c:8428–8431

}

static int roq_file_exists(const char *path) {
    struct stat st;
    return (stat(path, &st) == 0) ? 1 : 0;
}

/* ── (a) NO-MUTATION ──────────────────────────────────────────────────
 *