Agent Skills: requirements

This skill should be used when the user asks about "Effect services", "dependency injection", "Effect.Tag", "Context.Tag", "Layer", "Effect.provide", "Effect.provideService", "service implementation", "managing dependencies", "Layer.succeed", "Layer.effect", "Layer.scoped", "composing layers", "Layer.merge", "Layer.provide", "default services", "layer memoization", "testability", "test layers", "mock services", or needs to understand how Effect handles the Requirements (R) type parameter.