v1.1.1b1

1.1.1b1 — ZFP leased lines localhost clobber fix (#294)

Beta release to let leased-line ZFP users verify the fix before a
stable 1.1.1 cut. Install via `pip install --pre xbbg==1.1.1b1`.

Headline fix:
- ZFP over leased lines no longer spends 30-60s trying localhost:8194
  at session start before falling through to Bloomberg endpoints.
  SessionOptions produced by ZfpUtil::getOptionsForLeasedLines were
  being clobbered at index 0 by the direct-transport fallback.
  Fixed by restructuring EngineConfig's transport surface as a
  Transport enum (Direct / Zfp) where the clobber is unrepresentable.

Also in this release (see CHANGELOG [1.1.1b1] for full details):
- BQL secondaryColumns (DATE/CURRENCY) now extracted from responses
  (#288, refs #289/#290/#291)
- xbbg-async cache hot paths moved to ArcSwap + DashMap (p99.9 latency
  improvements up to ~19,000x under 1000 readers)
- Service-open calls now non-blocking (openServiceAsync + nested
  dispatch) so subscription data flows while services are opening
- Subscription lifecycle aligned with BLPAPI SDK v3.11.6+ contract
  for transient blips vs terminal disconnection
- Keep-alive and slow-consumer tunables exposed on EngineConfig
- AuthorizationRevoked handled mid-session on both worker types
- Multiple @xbbg/core error-wrapping consistency fixes

Closes #294