Adds four Windows counterparts to the existing Mac Studio jobs, all on
the free windows-latest runner (4 vCPU / 16 GB / 14 GB SSD; no premium
SKU). Mirrors the Mac coverage 1:1 in name and assertion shape so the
PR-status grid reads "Mac Studio * = Windows Studio *":
studio-windows-ui-smoke.yml -> "Windows Studio UI CI"
studio-windows-inference-smoke.yml -> "Windows Studio GGUF CI" (3 jobs)
studio-windows-update-smoke.yml -> "Windows Studio Update CI"
studio-windows-api-smoke.yml -> "Windows Studio API CI"
Key Windows differences vs the Mac mirrors:
* runs-on: windows-latest (free public runner)
* defaults.run.shell: bash so curl / jq / heredoc steps go through
Git Bash (windows-latest's default shell is pwsh)
* Install step uses pwsh + ./install.ps1 --local --no-torch (NOT
bash install.sh; install.sh has no Windows branch and would hit
apt-get / brew calls). install.ps1 is Studio's documented Windows
installer and is exercised by release-desktop.yml today.
* Asserter looks for bin-win-cpu-x64 (the prebuilt that
windows-latest, no GPU, hits via studio/install_llama_prebuilt.py
line 1272). Source-build fallback is rejected as a Studio bug.
* setup-python: drop cache:'pip' across all four (install.ps1 +
setup.ps1 use uv; setup-python's post-step otherwise fatal-errors
with "Cache folder path is retrieved for pip but doesn't exist").
* api-smoke: do NOT pin STUDIO_AUTH_DIR (Mac mirror hardcodes
/Users/runner/...). studio_api_smoke.py defaults to
Path.home()/'.unsloth'/'studio'/'auth' which resolves correctly
on every OS.
* inference-smoke: drop the Linux-only `ss -tln` diagnostic line.
No code changes to install.ps1, setup.ps1, install_llama_prebuilt.py,
or unsloth_cli/commands/studio.py -- Windows is already fully wired
in those (~30 host.is_windows branches in the prebuilt installer +
three sys.platform=='win32' branches in the Studio CLI).
Also fixes the Linux Chat UI Tests "extra turn" timeout (run
25487410101 / job 74786523982). The send_and_wait predicate used
non-empty assistant bubble count vs a baseline. When gemma-3-270m
emitted an empty turn (legitimate model output), the empty bubble
counted toward total but NOT toward the non-empty baseline, and the
next turn's wait expected nonempty >= baseline + 1 forever -- never
satisfied. Refactor:
* Snapshot TOTAL bubble count before send (proves new placeholder
rendered, regardless of content).
* Wait for Send-button-attached AND Stop-button-detached as the
"previous turn finished" signal.
* Treat empty bubbles as legitimate model output, not test failure.
* Add page.on('response') listener for /v1/chat/completions and
log status distribution + 4xx count after the 5-turn loop, so a
flake is debuggable from the CI log without artifact spelunking.