Add faithful single-choice chat results, tool stream activity, error-frame retries, and isolated protocol caching.
Reject empty cached completions with the same value predicate as transport, add regression coverage, and adopt Apache-2.0.
Classify empty completions as transient per human ruling (fixes flaky
real-gateway smoke and prevents caching empty responses), rename the
factory injection parameter gate to breaker per the frozen design,
rewrite the probe-entry cleanup without except BaseException, declare
python-dotenv explicitly, add a mid-backoff cancellation test, and
record all implementation errata in the design and architecture docs.