v0.5.3

Added

• stream_reservation() accepts an optional caller-supplied
  idempotency_key, enabling framework adapters to preserve stable upstream
  call identities. Commit and release keys are derived from it.
• raise_on_commit_failure=True surfaces a CyclesProtocolError only after
  known spend has been persisted and recovery queued. settlement_error and
  release_error expose the corresponding best-effort outcome when callers
  keep the default non-raising behavior.

Fixed

• Lifecycle and streaming paths no longer release a reservation after a
  recognized commit rejection. The guarded action already spent the resource;
  releasing at that point returned budget for known spend.
• Sync and async decorator lifecycles now release only when the guarded
  function itself fails. Missing required actual configuration fails before
  reservation, post-action settlement/setup errors never release known spend,
  and a failing or invalid actual callback commits the estimate with
  metadata.actual_source="estimate".
• Async cancellation while the guarded function is running now follows the
  same best-effort release path as ordinary function exceptions.
• The shared CR-BOUNDARY-001 conformance binding follows the strengthened
  missing-actual preflight regression, keeping the 12-scenario durable profile
  executable after the test was renamed.
• Stream first-attempt requests use the typed SDK request models while durable
  retries retain their schema-equivalent journal dictionaries.
• The LangChain callback example now uses the managed reservation lifecycle,
  normalized AIMessage.usage_metadata, cached-input pricing, a stable run key,
  and concurrent run tracking. It enables callback error propagation so reserve
  denial cannot be swallowed, and it no longer drops failed commit responses.