effect-uai structured-output

The model returns a typed JSON object instead of prose. One Effect Schema is used twice: provider-side as a JSON Schema constraint, and locally as a decoder for the assembled response.

Reach for this when the user says any of:

• "I want the model to fill out a form / return a typed object"
• "Extract entities / fields / a recipe from this input"
• "Classify this into a structured shape"

Define the contract