chore: Improve Windows build time [experiment]

[danskmt]

Pull Request Submission Checklist

• Follows CONTRIBUTING guidelines
• Commit messages are release-note ready, emphasizing what was changed, not how.
• Includes detailed description of changes
• Contains risk assessment (Low | Medium | High)
• Highlights breaking API changes (if applicable)
• Links to automated tests covering new functionality
• Includes manual testing instructions (if necessary)
• Updates relevant GitBook documentation (PR link: ___)
• Includes product update to be announced in the next stable release notes

What does this PR do?

Replaces the single Windows build job that ran build clean-golang build-fips serially (~14m) with two parallel jobs: build windows amd64 and build windows fips amd64. Updates sign windows amd64 to require both jobs.

Where should the reviewer start?

• .circleci/config.yml — Windows build-artifact workflow jobs and sign windows amd64 requires

How should this be manually tested?

1. Push branch and run test_and_release in CircleCI.
2. Confirm build windows amd64 and build windows fips amd64 run in parallel.
3. Compare each job’s make step duration to the previous ~14m combined step (~7–8m per job expected).
4. Confirm sign windows amd64 succeeds on main/release branches after both build jobs complete.

What's the product update that needs to be communicated to CLI users?

None. CI-only change with no user-facing impact.

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

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✅	Open Source Security	0	0	0	0	0 issues
✅	Licenses	0	0	0	0	0 issues
✅	Code Security	0	0	0	0	0 issues

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