Agent Skills: effect-best-practices

Idiomatic Effect-TS patterns for TypeScript functional programming. USE THIS SKILL WHEN: Writing new Effect services or layers, debugging Effect type errors (layer composition, error types), choosing between Effect patterns, setting up Effect testing. TRIGGERS ON: 'effect pattern', 'Layer.provide', 'Context.Tag', 'effect service', 'effect error', 'effect test', 'idiomatic effect'. NOT FOR: general TypeScript without Effect.