Both transport paths now share one verdict: a stream is complete on
[DONE] or on finish_reason followed by measured usage and a clean EOF
(both modes; missing_done only governs real truncation). Outcomes follow
the design's first-match table: upstream_error finishes stay transient,
fidelity mode delivers reasoning-only/length results, text mode raises
ResultInvalid for content-less length/filter endings, and non-stream
fidelity judges before building the snapshot so truncated tools reach
tool_truncated. Projections honour the reasoning alias, dialect warnings
are bounded, and responses carry finish_reason and stream_end.
Red: 39 of 46 tests in tests/unit/test_completion_transport.py failed
before this change (e.g. eof_after_finish raised 保真响应缺 [DONE];
reasoning-only length raised empty_completion; reasoning-only stream hit
the TTFT watchdog, re-confirmed by disabling alias liveness).
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.
iomgaa