6.1.1

Changed

• mapAPIErrorToLLMError now says why it has no default:, and what the next APIError case maps
  to. swift-api-client 6.0.0 adds emptyResponseBody(statusCode:outputType:), which this switch
  does not handle, so raising the pin breaks the build — confirmed rather than assumed: compiled
  the same switch against the 6.0.0 source and got error: switch must be exhaustive. No
  default: was added. The build break is the mechanism, the one LLMError.isRetryable already
  documents for its own switch, and no fallback would be right: unknown(_:) drops whatever the
  new case carries, and every other case claims something specific that the retry policy then acts
  on. @unknown default was measured too — it downgrades the error to a warning, and a warning
  does not fail swift test, so the wrong mapping would ship in silence. The pin is
  from: "5.0.0", so nothing resolves 6.0.0 until someone raises that line; the one-line addition
  belongs in that same edit, and it is case .emptyResponseBody: return .emptyResponse.