[Sprint 19] add dotnet format gate before the pre-push build

[mpaulosky]

Summary

Add a dotnet format step to the local .github/hooks/pre-push gate so formatting runs before the build gate.

Acceptance Criteria

• The pre-push hook runs dotnet format before the build step
• The hook fails clearly when formatting changes are required or formatting fails
• Any directly related workflow/process docs stay accurate
• Existing gate ordering remains coherent after the new step is inserted

[github-actions]

📋 Assigned to Boromir (DevOps / Infra)

Issue: #289 — [Sprint 19] add dotnet format gate before the pre-push build

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Boromir, work on issue #289