Add 260+ Claude Code skills from skills.sh

Complete collection of AI agent skills including:
- Frontend Development (Vue, React, Next.js, Three.js)
- Backend Development (NestJS, FastAPI, Node.js)
- Mobile Development (React Native, Expo)
- Testing (E2E, frontend, webapp)
- DevOps (GitHub Actions, CI/CD)
- Marketing (SEO, copywriting, analytics)
- Security (binary analysis, vulnerability scanning)
- And many more...

Synchronized from: https://skills.sh/

Co-Authored-By: Claude <noreply@anthropic.com>

dev-browser/CONTRIBUTING.md

@@ -0,0 +1,25 @@
+# Contributing to dev-browser
+
+Thank you for your interest in contributing!
+
+## Before You Start
+
+**Please open an issue before submitting a pull request.** This helps us:
+
+- Discuss whether the change aligns with the project's direction
+- Avoid duplicate work if someone else is already working on it
+- Provide guidance on implementation approach
+
+For bug reports, include steps to reproduce. For feature requests, explain the use case.
+
+## Pull Request Process
+
+1. Open an issue describing the proposed change
+2. Wait for maintainer feedback before starting work
+3. Fork the repo and create a branch from `main`
+4. Make your changes, ensuring tests pass (`npm test`) and types check (`npx tsc --noEmit`)
+5. Submit a PR referencing the related issue
+
+## Questions?
+
+Open an issue with your question - we're happy to help.