degradation.ts: Fix service degradation not reverting after recovery window expires

[Kingsman-99]

Description

src/degradation.ts puts a service into degraded mode after repeated failures, but the recovery window timer does not start until the first success after the failure threshold. It should start immediately when the threshold is crossed, so recovery is bounded in time.

Acceptance Criteria

• The recovery window timer starts as soon as the failure threshold is crossed
• After the window expires, the service state reverts to healthy regardless of subsequent calls
• A test confirms the revert happens at the correct wall-clock time
• Unit tests pass

Context

• Target file: src/degradation.ts
• Use src/timeMachine.ts in tests to control time without setTimeout delays

[Mormentz]

@Mormentz has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I'd like to take this. I'll fix the recovery timer to start when the failure threshold is crossed, verify time-based recovery with timeMachine, and add focused tests. Ready to start immediately.

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[coredevdave-cmd]

@coredevdave-cmd has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

i would like to work on this

ℹ️ Repo Maintainers: To accept this application, review their application or assign @coredevdave-cmd to this issue.

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Congratulations, @coredevdave-cmd! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Third Campaign campaign!

@coredevdave-cmd's PR #718 was approved and merged by @Kingsman-99.

🏆 @coredevdave-cmd: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (923 total points). Track your full progress on GrantFox.

👏 Great work, @coredevdave-cmd! Keep contributing to Stellar-split.

[drips-wave]

This issue has been completed by @coredevdave-cmd as part of the Stellar Wave Program's 8th Wave 🥳

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