ci(github): migrate to JSON-based NuGet versioning strategy

[ncipollina]

🚀 Pull Request

📋 Summary

Migrates LayeredCraft.StructuredLogging from the MSBuild VersionPrefix publish approach to the new JSON-based versioning strategy introduced in devops-templates#21.

• Adds eng/package-versioning.json — version manifest with single strategy, prefix 1.1.8
• Adds publish-preview.yaml — triggers on push to main, publishes 1.1.8-preview.<runNumber>
• Adds publish-release.yaml — triggers on tag v*, validates tag against manifest, publishes stable version and creates GitHub Release
• Removes build.yaml — replaced by the two new caller workflows above
• Updates LayeredCraft.StructuredLogging.slnx — reflects new workflow files and adds eng/package-versioning.json to Solution Items

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✅ Checklist

• My changes build cleanly
• I've added/updated relevant tests
• I've added/updated documentation or README
• I've followed the coding style for this project
• I've tested the changes locally (if applicable)

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🧪 Related Issues or PRs

Depends on LayeredCraft/devops-templates#21 — merge that first.

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💬 Notes for Reviewers

Caller workflows reference @main on devops-templates, so devops-templates#21 must be merged before this PR is merged — otherwise the reusable workflows won't resolve.

To test after both are merged: go to Actions → Publish Preview → Run workflow on main.

Directory.Build.props still has VersionPrefix — it's no longer used by CI but can be cleaned up in a follow-up once the new approach is validated.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Reference reusable workflow from a resolvable ref

This workflow now depends on LayeredCraft/devops-templates/...@main, so every publish run will fail with “workflow was not found” whenever main does not yet contain publish-preview.yml/publish-release.yml (the current state that this PR itself calls out as an external dependency). Because this repo no longer has a fallback build/publish workflow, that makes main pushes and release tags non-runnable until the upstream branch state matches; pinning to a released tag/SHA that already contains these files avoids that breakage.

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