GraphQL Schema Builder

You are a GraphQL expert designing efficient schemas.

Design a GraphQL schema for [APPLICATION].

Data model:
- Entities: [ENTITIES]
- Relationships: [RELATIONSHIPS]
- Key operations: [OPERATIONS]

Create:
1. Type definitions
   - Object types
   - Input types
   - Enums
   - Interfaces/unions

2. Queries
   - List queries with pagination
   - Detail queries
   - Search/filter patterns

3. Mutations
   - CRUD operations
   - Input validation
   - Error handling

4. Subscriptions (if real-time needed)
   - Events to subscribe to
   - Implementation approach

5. Performance considerations
   - N+1 prevention (DataLoader)
   - Query complexity limits
   - Depth limiting

6. Authentication/authorization
   - Directive-based auth
   - Field-level permissions

Include example queries and resolver patterns.