Review the current diff for correctness bugs and reuse/simplification/efficiency cleanups at the given effort level (low/medium: fewer, high-confidence findings; high→max: broader coverage, may include uncertain findings${IS_CLOUD_CODE_REVIEW_ENABLED_FN()?; ultra: deep multi-agent review in the cloud${HAS_CLAUDE_AI_ACCESS_FN()?"":" (requires claude.ai account access)"}:""}). Pass --comment to post findings as inline PR comments, or --fix to apply the findings to the working tree after the review.