Tests: race on time.Local in runWrite helper; TestSecretsSetRetriesWithTheSameIdempotencyKey order-dependent #55

Found by the Opus QA review of #54 (pre-existing, not caused by it):

• TestTriggersJSONAndTokens fails under -race: the runWrite test helper mutates time.Local concurrently.
• TestSecretsSetRetriesWithTheSameIdempotencyKey fails depending on test order (-shuffle=on).
  CI does not run -race or -shuffle, so both pass today. Fix the helpers so the suite is race- and order-clean, then consider adding -race to CI.