feat: add API framework skills (GraphQL, REST, gRPC)

[njg7194]

Summary

This PR adds three comprehensive API framework skills for AI CLI tools:

1. GraphQL (skills/graphql/)

• Schema design patterns and best practices
• Query and mutation examples
• Introspection queries
• Subscriptions (WebSocket)
• Authentication patterns
• Performance optimization (DataLoader, caching)

2. REST API (skills/rest-api/)

• HTTP methods and status codes
• URL design best practices
• OpenAPI/Swagger specification
• Authentication (JWT, API Key, OAuth)
• API versioning strategies
• Rate limiting patterns

3. gRPC (skills/grpc/)

• Protocol Buffers basics
• All RPC types (unary, streaming)
• grpcurl usage examples
• Authentication (mTLS, JWT)
• Error handling with status codes
• Performance tuning

Structure

Each skill follows the standard structure:

skills/<name>/
├── SKILL.md           # Main skill file with quick reference
└── references/        # Detailed documentation
    ├── auth.md
    ├── ...

Testing

• All SKILL.md files have proper frontmatter
• Reference files are properly linked
• Code examples are tested

Related

This addresses the need for API development skills in modern AI-assisted development workflows.

[runkids]

Hi @njg7194,

Thanks for the contribution! However, this repo (skillshare) is a CLI tool for managing skills, not a skills collection.

These API framework skills should be in a separate skills repository. You can:

1. Create your own skills repo 🤩 (e.g., your-username/my-skills)
2. Users can then install them with skillshare install your-username/my-skills

The only skill in this repo is the built-in skillshare skill that teaches AI how to use the CLI itself.