## ADDED Requirements

### Requirement: Define Superstruct validators for data shapes

The package SHALL export Superstruct schema definitions for validating runtime data shapes (request payloads, configuration objects, etc.).

#### Scenario: Validator validates correct data

- **WHEN** data matching the schema is passed to the validator
- **THEN** the validator SHALL return the validated data without throwing

#### Scenario: Validator rejects invalid data

- **WHEN** data not matching the schema is passed to the validator
- **THEN** the validator SHALL throw a `StructError` with details about the validation failure

### Requirement: Validator composability

Superstruct schemas SHALL be composable — schemas can reference other schemas for nested object validation.

#### Scenario: Nested object validation

- **WHEN** a schema defines a nested object field using another Superstruct schema
- **THEN** the nested schema SHALL be applied during validation of the parent

### Requirement: Optional and default fields

Superstruct schemas SHALL support optional fields (`optional()`) and fields with default values (`defaulted()`) for partial updates or configuration defaults.

#### Scenario: Optional field omitted

- **WHEN** an optional field is omitted from input data
- **THEN** the validator SHALL accept the data and not require the field

#### Scenario: Default value applied

- **WHEN** a field with a default value is omitted from input data
- **THEN** the validator SHALL apply the default value in the returned data