[ci]: slience some clang-tidy warnings

the warnings on r_readdir(), img_load_gif() and strcpy seems to be false
positives. the warning about fmt being unused is valid, but not worth
fixing with additional #ifdef guards.

use `assert` to silence the false positive cases when possible,
otherwise use a NOLINT comment with an explanation.

autoreload.c

@@ -79,7 +79,7 @@ void arl_setup(arl_t *arl, const char *filepath)
 	if (base != NULL) {
 		arl->filename[++base - filepath] = '\0';
 		add_watch(arl->fd, &arl->wd_dir, arl->filename, IN_CREATE | IN_MOVED_TO);
-		strcpy(arl->filename, base);
+		strcpy(arl->filename, base); /* NOLINT: basename will always be shorter than fullpath */
 	}
 }