get:
  tags:
    - Session
  summary: Start hosted UI sign-in
  description: Redirects the browser to Cognito hosted UI with PKCE S256. Sets the oauth cookie.
  operationId: get-api-auth-login
  security: []
  parameters:
    - name: returnTo
      in: query
      required: false
      description: Relative path to return to after sign-in.
      schema:
        type: string
        default: /
      example: /invoices
  responses:
    "302":
      description: Redirect to Cognito hosted UI.
    "500":
      description: Cognito is not configured.
      content:
        application/json:
          schema:
            $ref: ../components/schemas.yaml#/Error
          example:
            error:
              code: INTERNAL_ERROR
              message: Cognito is not configured.
              correlationId: 11111111-1111-4111-8111-111111111111