test(server): ServerSecretStore race test is flaky #249

What: apps/server/src/auth/ServerSecretStore.test.ts › "returns the persisted secret when concurrent creators race" failed once, then passed three runs in a row on the same tree.
Why: unknown; it looks timing-dependent (a race test), and it is outside the code #247 changes.
So what: an agent reproduces it in a repeat loop and makes the test deterministic; no user action needed.

Outcome

The race test passes reliably.

Problem Statement

• macOS, Node 26.8.1, pnpm exec vp test run src/issues src/auth from apps/server on branch feat/235-feature-map (feat(web): a Map tab draws each project's feature map from GitHub #247): 1 failed, 169 passed.
• pnpm exec vp test run src/auth three more times: 116 passed each time.

Elon record

• Requirements and who asked: the user's standing rule to file problems found during other work; a flaky test erodes trust in the server suite.
• Deleted: nothing yet; the cause is not known.
• Bottleneck: reproducing the failure on demand.
• Checked myself: one failure and three clean reruns of the same files on the same tree.

Acceptance criteria

• The test passes in a repeat loop (for example 50 runs).

Non-goals

• Changing the secret store's behaviour unless the flake reveals a real race.

Blockers

• None.

Required proof

• A repeat-loop run with no failures.