test(windows): guard clean MCP stdio startup

[lorenzozanee]

What does this PR do?

Adds a native Windows MCP stdio regression guard for #654. The guard isolates daemon runtime cleanup and rejects the reported path-not-found diagnostics after a successful initialize/tools/list exchange.

Checklist

• Every commit is signed off (git commit -s) — required, CI rejects
  unsigned commits (DCO, see CONTRIBUTING.md)
• Tests pass locally (make -f Makefile.cbm test)
• Lint passes (make -f Makefile.cbm lint-ci)
• New behavior is covered by a test (reproduce-first for bug fixes)

Fixes #654

Supersedes #2097（原PR分支已删，按原提交重建）

[github-actions]

Thanks for opening this — it has been seen, and it is queued.

This note is automated, but it is not a brush-off: it exists so you know where your PR stands instead of having to guess from silence.

Current review status: working through a backlog. 0.9.1-rc.1 is out, so the release freeze that held reviews is over — but it left a large queue of open pull requests behind it, and we are reading through them oldest-first. The background is in discussion #1144.

What that means for this PR, concretely:

• It will not be closed for inactivity. No stale bot touches pull requests here.
• It may still sit a while before a human reads it. That is on us, not on you.
• Older PRs are read first, so a recent one is not being skipped — it is behind a queue.

Things that will genuinely speed it up whenever review does happen:

• Keep it rebased on main — the tree is moving quickly right now, and a conflicting branch cannot be reviewed as the diff you intended.
• Get CI green, or say which failures you believe are pre-existing.
• Keep the change to one claim. Bundled features and refactors get split before they get merged, which costs you a round trip.
• Every commit needs a sign-off (git commit -s) — CI enforces DCO.

If this fixes a bug, a reproduction we can run is worth more than a description of the symptom.

Thanks for contributing, and sorry in advance for the wait.

[DeusData]

Thank you for building a native Windows MCP stdio guard for #654 — that platform is where our hardest bugs hide and guards there are worth a lot.

Before you spend any time on this one: I think it may be a double-submit, and I would rather ask than close it on you.

This PR and #2217 are the same guard for the same issue, opened thirteen seconds apart. #2217 looks like the fuller version:

	#2213 (this one)	#2217
tests/windows/test_mcp_stdio.py	+57	+59
tests/windows/mcp_stdio.py	—	+1
scripts/test-windows.ps1	+1	+1
description	rejects path-not-found diagnostics	also captures stderr deterministically, handles the Spanish diagnostic text

If that is right, #2217 is the one to keep and this can be closed — but it is your work and your call, so tell me which you want and I will do the rest. If they are actually different and I have misread, say so and I will review both.

Whichever survives needs the same two things:

The dco check is red. Your commits carry no Signed-off-by trailer — a headline with an empty body, so there is nothing to parse. (Not the blank-line trap, where a sign-off falls outside the trailer block and git's parser ignores it while grep still sees it; here there is no trailer.)

git commit --amend -s          # single commit
git rebase --signoff origin/main   # several
git push --force-with-lease

test / test-msan is our problem, not yours. That lane fails on its Docker image build whenever apt.llvm.org is flaky, and it reddens PRs that have nothing to do with it. Please ignore it — I track it separately and it will not block this.

#2241 and #2242 both merged today after review. Good work on those.