fix(workspace): treat '/' and '\' as the same separator in root matching (#1718)

[umi008]

What does this PR do?

--approve-sensitive never lifted the sensitive-root refusal on Windows for paths under Program Files, because the grant is recorded from cbm_canonical_path (backslashes) while the indexer hands the candidate already normalized to /. ws_is_ancestor_or_equal compared the raw bytes, so the recorded grant never matched the candidate and the escape hatch stayed dead exactly where it is needed most.

The comparison now treats / and \ as the same separator on the component boundary, consistent with ws_is_sep everywhere else in this module. The containment rule (a separator byte is never part of a component name) is unchanged.

The ws_paths_equal home-directory rule in cbm_workspace_classify_root uses the same helper, so home detection becomes robust to separator spelling as well. No classification semantics changed beyond separator equivalence.

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)

[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.

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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.