smoke: follow 307 redirect, 20-min readiness window, readable logs

smoke: patch upstream cosyvoice warmup call (stream=True keyword)

smoke: resample stand-in voice to 48k before boot

smoke: kill full process tree on all exit paths

smoke: pyarrow<16 pin + pre-boot CosyVoice import check

smoke: --no-sync on post-install uv runs (upgrade no longer reverted)

smoke: typing_extensions fix + correct readiness grep + traceback fast-fail

smoke: bootstrap pip via ensurepip (base image lacks pip)

smoke: install python3.11 via deadsnakes to match Dockerfile

script: GPU end-to-end boot verification