docs(870): correct stale CLAUDE.md toolchain, analyzer-config and coverage-threshold citations

[drmoisan]

Summary

• Corrects five stale prose sites in CLAUDE.md (the repository's only production file in this change): the two "toolchain step 4" test-command citations, the .editorconfig/.globalconfig analyzer-configuration citations (two sites), and the repository-wide coverage-figure line, plus a companion edit to a paragraph that a sibling item (Bug: test-evidence-projection-convention-and-identity-leak-tooling #873) had already made depend on the corrected text.
• The two toolchain step-4 entries previously named vstest.console.exe ... /EnableCodeCoverage ... directly. They now describe the actual route in use: the test: MSTest with Coverage (Koverage) VS Code task (or scripts/vscode/Invoke-MSTestWithCoverage.ps1 invoked directly), which wraps an inner vstest.console.exe call inside an outer dotnet-coverage collect process, and states why the built-in /EnableCodeCoverage collector is deliberately withheld from the inner call (it conflicts with the outer instrumentation).
• The two analyzer-configuration citations previously named a nonexistent .globalconfig file alongside the real .editorconfig; both are corrected to name .editorconfig only.
• The repository-wide coverage-figure line is replaced with three lines stating the settled per-language figures (C# line 80%/branch 75%, PowerShell line 80% with no branch floor because Pester does not measure branch coverage), together with the decision date (2026-09-11) and issue reference (Coverage threshold contradiction remains: CLAUDE.md/csharp.md say 80%, general-unit-test.md/quality-tiers.md say 85%/75%, and two live gates disagree #563).
• A companion edit corrects the "Committed Test Evidence Format" paragraph that explained why the toolchain steps passed explicit /ResultsDirectory and /Logger switches — a sibling item (Bug: test-evidence-projection-convention-and-identity-leak-tooling #873) had added that paragraph and those switches to the same two lines while this item was in flight; since this change removes the switch list from both toolchain entries, the paragraph is re-attributed to the script that actually supplies those values (Invoke-MSTestWithCoverage.ps1) rather than left citing text that no longer exists.
• Documentation-only change. No source, build, or test file is touched, so no formatter/linter/type-checker/test-runner gate applies (recorded explicitly in the plan's Phase 2 rather than left as a silent omission).

Context: conflict with a concurrently-merged sibling item

This branch was prepared and initially planned before issue #873 merged. #873's commit aa6bf5f30 rewrote the same two CLAUDE.md lines this item corrects (adding explicit /ResultsDirectory: and /Logger:trx;LogFileName= switches) and added the dependent paragraph described above. After merging origin/main into this branch, the plan was revised in place (revision round 3, then round 4 for two mechanical preflight defects: a stale local main ref in the base-commit computation, and a dropped list-item indent) to re-derive its "current text" citations against the merged tree, add the companion paragraph correction as new task P1-T5, and confirm #873 had not already accomplished any part of this item's substantive goal (it had not: /EnableCodeCoverage was still present, and none of the script name, task label, or dotnet-coverage wrapper text had been introduced).

Test plan

• All 8 acceptance criteria in spec.md verified and checked off (see feature folder evidence under evidence/qa-gates/).
• Change-footprint gate: diff against the merge base with origin/main (e4a337505af5ce0c53641d3a89343f20c1e2c6c1) shows exactly one path outside this item's own feature folder and promotion records: CLAUDE.md.
• No toolchain gate applies (documentation-only change; rationale recorded in the plan and in evidence/qa-gates/no-toolchain-rationale.md).
• Worktree clean; branch pushed.

🤖 Generated with Claude Code

https://claude.ai/code/session_012YZxqEe1udErQiYYt6Bb2d