feat(skills): add documentation-lookup, bun-runtime, nextjs-turbopack; feat(agents): add rust-reviewer

Made-with: Cursor

skills/nextjs-turbopack/SKILL.md

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+---
+name: nextjs-turbopack
+description: Next.js 16+ and Turbopack — incremental bundling, FS caching, dev speed, and when to use Turbopack vs webpack.
+origin: ECC
+---
+
+# Next.js and Turbopack
+
+Next.js 16+ uses Turbopack by default for local development: an incremental bundler written in Rust that significantly speeds up dev startup and hot updates. Use this skill when working with Next.js 16+ or tuning build performance.
+
+## Core Concepts
+
+- **Turbopack**: Incremental bundler for Next.js dev. Uses file-system caching so restarts are much faster (e.g. 5–14x on large projects).
+- **Default in dev**: From Next.js 16, `next dev` runs with Turbopack unless disabled.
+- **Production**: Next.js production builds still use the existing production bundler (webpack-based); Turbopack is focused on dev today.
+
+## When to Use Turbopack vs Webpack
+
+- **Turbopack (default dev)**: Use for day-to-day development. Faster cold start and HMR, especially in large apps.
+- **Webpack (legacy dev)**: Use only if you hit a Turbopack bug or rely on a webpack-only plugin in dev. Disable with env or flag (e.g. `--no-turbopack` if your version supports it).
+- **Production**: No change; production build pipeline is unchanged.
+
+## Commands
+
+```bash
+# Dev with Turbopack (Next.js 16+ default)
+next dev
+
+# Build (unchanged; not Turbopack)
+next build
+
+# Start production server
+next start
+```
+
+## File-System Caching
+
+Turbopack caches work on disk so that:
+
+- Restarts reuse previous work; second run is much faster.
+- Large projects see 5–14x faster compile times on restart in practice.
+- Cache is typically under `.next` or a similar project-local directory; no extra config needed for basic use.
+
+## Bundle Analyzer (Next.js 16.1+)
+
+Next.js 16.1 introduced an experimental Bundle Analyzer to inspect output and find heavy dependencies:
+
+- Enable via config or experimental flag (see Next.js docs for your version).
+- Use to optimize code-splitting and trim large dependencies.
+
+## Best Practices
+
+- Stay on a recent Next.js 16.x for stable Turbopack and caching behavior.
+- If dev is slow, ensure you're on Turbopack (default) and that the cache isn't being cleared unnecessarily.
+- For production bundle size issues, use the Bundle Analyzer and `next/bundle-analysis` or equivalent tooling.
+- Prefer App Router and server components where possible; they align with current Next.js and Turbopack optimizations.
+
+## When to Use This Skill
+
+Use when: developing or debugging Next.js 16+ apps, diagnosing slow dev startup or HMR, or optimizing production bundles with Next.js tooling.