Refactor a PR branch to meet a specific diff-size target while improving performance, correctness, and simplicity. Use when finishing PR work, when a diff is too large, when asked to "clean this up before merge", "reduce the changeset", "simplify this PR", "get this ready for review", "finish up this PR", "make this smaller", "optimize this branch", or any request to shrink a branch's footprint while preserving or improving its value. Always invoke before marking PR work complete or saying a PR is ready for review.
