simplify

<objective> Review all changed files for reuse, quality, and efficiency. Fix any issues found. Three-phase workflow: 1. Identify changes via `git diff` 2. Review through three lenses: reuse, quality, and efficiency 3. Aggregate findings and fix each issue directly Arguments: - Optional git ref or file path — scope the review (e.g., `$simplify src/auth/` or `$simplify HEAD~3`) - If no argument, reviews all uncommitted changes </objective> <process> ## Phase 1: Identify Changes Run `git diff` (or `git diff HEAD` if staged changes exist) to see what changed. If no git changes, review the most recently modified files. If user provided a scope argument: - If it looks like a path (contains `/` or `.`), run `git diff -- <path>` - If it looks like a ref (HEAD~N, commit hash, branch name), run `git diff <ref>...HEAD` - Otherwise, try path first, then fall back to ref Extract changed files list and full diff content. If no changes found, report: "No changes to review." and stop. ## Phase 2: Review Through Three Lenses Use parallel reviewers when the runtime and user authorization make delegation cheap; otherwise do the same review locally. The important part is the three lenses, not the mechanics. ### Lens 1: Code Reuse Review Review the diff for duplication and missed reuse opportunities. For each change: 1. Search for existing utilities and helpers that could replace newly written code. Common locations are utility directories, shared modules, and adjacent files. 2...