chore: Prepare for perf work — quiet test logging and ignore perf/

Lower com.retailsvc test logging from debug to info to avoid skewing
load-test profiles, ignore perf/ artifacts, and mark the completed
refactor plan as done.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: thced

.gitignore

@@ -36,3 +36,6 @@ build/
 
 ### Claude Code per-developer settings ###
 .claude/settings.local.json
+
+### Performance recordings ###
+perf/