claudetool: add "related files" detection to codereview tool

diff --git a/claudetool/testdata/add_skipped_test.txtar b/claudetool/testdata/add_skipped_test.txtar
index 95000cc..099ebdd 100644
--- a/claudetool/testdata/add_skipped_test.txtar
+++ b/claudetool/testdata/add_skipped_test.txtar
@@ -19,6 +19,8 @@
 Add skipped test
 
 -- .run_test --
+# Errors
+
 Test regressions detected between initial commit (2cdfdc5009e364add9a263909472f85eb08480ed) and HEAD:
 
 1: sketch.dev.TestP: New test is skipped