Adding custom GraphQL queries and mutations using GraphQLSchemaFactory. Use this skill when the developer wants to add custom GraphQL endpoints, create custom queries or mutations, add business logic to the API layer, build custom resolvers, inject backend services (identity, tenancy, CMS use-cases) into their GraphQL schema, or build dynamic GraphQL inputs from CMS models. Covers the full pattern from simple queries to complex resolvers with dependency injection and permission transformers.