* ci: run native Windows PR jobs in a separate workflow
GitHub re-runs failed jobs only after a whole run finishes, so slow Windows jobs blocked re-running failed Linux jobs. CI Windows now owns the native Windows jobs and the Windows x64 Python runtime target, with its own required 'windows checks passed' verdict.
Refs #6893
* ci: run Python PR jobs in a separate workflow
Python rarely fails while the Windows lanes run long, so the Python SDK suite and the Linux/Windows x64 runtime matrix move into CI Python. The three pull-request workflows can now be re-run without waiting for each other, and branch protection gains "python checks passed" beside the existing verdicts.
Refs #6893
* docs: record the three PR verdicts in the failover runbook
* test: pin the shared environment across the PR workflows
* test: read the python SDK lane from CI Python
* test(sdk): parse session JSONL frames in the keyless smoke
Node 24.19 returned only the first frame of a concatenated zstd log, so the single JSON.parse saw just the header; 24.22 returns every frame and the JSONL body broke the parse. Read frames explicitly and select the main session by its header so both versions agree.
imccyu