ci: prefer commit-specific Aiter S3 manifest

[gyohuangxin]

Summary

• Keep the existing S3-first Aiter wheel resolver
• When main/latest.json is stale, try commits/<Aiter SHA>/latest.json from S3 before falling back to GitHub artifacts
• Verify the commit-specific manifest commit matches the latest Aiter artifact SHA

Why

ATOM currently falls back to GitHub artifacts if CloudFront serves a stale Aiter main/latest.json. This lets ATOM still use S3 once Aiter publishes the immutable commit-specific manifest.

Depends on ROCm/aiter#4807.

Validation

• bash -n .github/scripts/download_aiter_wheel.sh
• git diff --check

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[github-actions]

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