Credential-store tests fail on the Windows runner with EPERM and 5 s timeouts

[wmadden-electric]

Timing-sensitive credential-manager tests keep failing on windows-latest and pass on re-run. Between 2026-08-18 and 2026-09-21:

• "holds no lock while the workspace name is fetched": 3 failures
• "re-decides adoption inside the lock": 4 failures, last on 2026-09-12
• "exchanges one refresh token once": 2 failures (e.g. run 35588710412)
• "lets only one of two waiting mutations clear the same crashed holder's lock": run 32833711949, 5 s timeout

At least four were EPERM on open(auth.json.lock) or rename(auth.json.<uuid>.tmp → auth.json), not timeouts. That suggests a real problem with two CLI processes writing credentials at once on Windows, not only slow tests. A related Windows flake also appeared in skills-project.test.ts (run 35194673695).

Recorded in the prisma-cli-v8 project ledger, which is being deleted at project close-out:

prisma-cli/.drive/projects/prisma-cli-v8/deferred.md

Line 500 in 4356b36

- **Windows CI: the credential-manager suite needs an owner** — two distinct timing-sensitive tests flaked on 2026-08-21 (`credential-manager.test.ts` "holds no lock while the workspace name is fetched", run 32477175789; `credential-manager-processes.test.ts` "exchanges one refresh token once", run 32497093995), both on pushes touching nothing near credentials. A third hit on 2026-08-24 (run 32737503671, PR #225): the "holds no lock" test again, failing on an EPERM temp-file rename on the Windows runner. Three flakes across two tests; the suite needs an owner.

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