v1.2.1

Three bug fixes in transport behaviour and a small set of godoc clarifications.
No API surface changes, no new dependencies.

Fixed

• retry.Transport: when Retry-After exceeds the configured maxDelay,
  the prior 5xx response is now drained and closed inside the transport and
  the call returns (nil, ErrRetryAfterExceedsMax). Previously the
  transport returned (resp, err) with resp.Body open, which violated
  the http.RoundTripper contract that a non-nil error implies the caller
  has nothing to close. When wrapped by http.Client (the standard
  ghkit.New path), the response was dropped unclosed, leaking the body
  and preventing connection reuse on every aborted retry.
• etag.Transport drift recovery: the post-cooldown probe predicate
  shifted from n%driftProbeEveryN == 0 to n%driftProbeEveryN == 1.
  Probes now fire on calls 1, 51, 101 after driftCooldown elapses (was
  50, 100, 150), shifting the probe burst to the start of the post-cooldown
  window and cutting recovery latency from 150 to 101 cacheable requests.
• etag.NewLRUCache: byteTotal accounting now decrements on count-cap
  evictions via a registered eviction callback. Previously, when the LRU's
  internal slot cap (default 4096) overflowed and the eldest entry was
  evicted, byteTotal was not adjusted; on workloads with more than 4096
  distinct cached entries combined with WithMaxCacheBytes, the
  over-counted total made the byte-budget loop evict real entries to
  compensate for phantom bytes, shrinking effective cache capacity.

Documentation

• retry.ErrRetryAfterExceedsMax godoc records the new contract: on this
  error resp is nil and the transport has already drained and closed
  the prior response.
• etag.WithKeyScope godoc clarifies that an empty scope is treated
  identically to omitting the option, and that combining WithCache with
  no scope fails construction with ErrKeyScopeRequired.
• ratelimit.WithUpstreamOptions godoc warns that type-mismatched values
  are silently dropped by the upstream constructor.
• etag package doc records the drift detector's tuning assumption: a
  transport handling fewer than roughly 100 cacheable requests after the
  cooldown window elapses will not complete recovery under the current
  private thresholds.
• ghkit.HTTPClient composition-order comment now lists the retry layer
  between oauth2 and ratelimit, matching the actual code.
• README retry recipe updated to match the new abort contract and to note
  that POST/PATCH retries with a body require req.GetBody.