components:
  schemas:
    TokenData:
      description: Authentication token payload with expiration metadata.
      type: object
      additionalProperties: false
      required:
        - token
        - expiration
      properties:
        token:
          description: Issued authentication token value.
          type: string
        expiration:
          description: RFC 3339 timestamp when the token expires.
          type: string
          format: date-time