fix: limit concurrent half-open probes

[poaspergillus]

Summary

• Add a dedicated configurable limit for concurrent HALF_OPEN circuit-breaker probes.
• Fail fast with the existing fallback behavior when the probe limit is reached.
• Protect lazy ethers loading with a single-probe circuit breaker and clear failed module loads so recovery can retry.
• Add focused coverage for HALF_OPEN probe limiting and ethers-service integration.

Validation

• npm run type-check: PASS
• Prettier check on all Limit concurrent half-open probes in circuit breaker #1166 files: PASS
• Focused ESLint on all Limit concurrent half-open probes in circuit breaker #1166 files: PASS
• Focused Vitest: 24/25 tests passed; the only failure is the pre-existing Failure History Cleanup test on the base branch.
• New HALF_OPEN concurrency test: PASS
• New ethersService test: PASS

Closes #1166

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@poaspergillus Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

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[RUKAYAT-CODER]

Well done on the job done so far!
Kindly fix workflow to pass

[poaspergillus]

@RUKAYAT-CODER

Thank you. I’ve fixed the workflow issue, and all 6 PR checks for #1281 are now passing.

I’ve also applied to the other open issues in this project, including the ones I submitted today.

Since I’m already familiar with the codebase and workflow, I’d appreciate being considered for those as well.

I’ll continue submitting focused changes, proper tests, and clean PRs.

[RUKAYAT-CODER]

Thank you for contributing to the project.