chore: ignore local codebase memory

Author: elkaix

.gitignore

@@ -25,6 +25,7 @@ reports/
 .superpowers/
 blackbox/
 # pythinker — local agent state (do not commit)
+.codebase-memory/
 .pythinker/
 .pythinker-review/
 .pythinker-review-flow/