Perform a structural and maintainability review of a PR or codebase diff — covering file-size blockers, abstraction quality, layer violations, type structural discipline, spaghetti branching, non-atomic mutations, stack-specific hygiene (Bun, Tailwind v4, Next.js 16, shadcn/ui), design purity (code-
Perform a structural and maintainability review of a PR or codebase diff — covering file-size blockers, abstraction quality, layer violations, type structural discipline, spaghetti branching, non-atomic mutations, stack-specific hygiene (Bun, Tailwind v4, Next.js 16, shadcn/ui), design purity (code-judo), and directness over magic (no speculative generality). Use when asked to review code quality,