Release v3.0.1

Added

• testing::handler_assert — typed assertion helpers for RfcOk<T>-returning handler unit tests (gated on rfc-types, no extra feature flag required). Covers the full api-bones payload surface:
  • payload<T> / list_payload<T> / cursor_payload<T> / keyset_payload<T> / bulk_payload<T> — extract typed data from RfcOk<T> without T: Debug
  • status / headers / etag_header — low-level header accessors
  • unwrap_ok / unwrap_list / unwrap_cursor / unwrap_keyset / unwrap_bulk — convenience unwraps for Result<RfcOk<T>, HandlerError>
  • unwrap_status — returns (StatusCode, T) in one call
  • unwrap_created — returns (StatusCode, HeaderMap, T) for CreatedAtResponse handlers
  • unwrap_err / unwrap_err_status — extract the error without a Debug bound on T