Change comment severity threshold to CRITICAL

.gemini/config.yaml

diff --git a/.gemini/config.yaml b/.gemini/config.yaml
index 31814ef..3987d00 100644
--- a/.gemini/config.yaml
+++ b/.gemini/config.yaml
@@ -1,7 +1,7 @@
 have_fun: false
 code_review:
   disable: false
-  comment_severity_threshold: HIGH
+  comment_severity_threshold: CRITICAL
   max_review_comments: -1
   pull_request_opened:
     help: false