ci: add versioning check via sandbox proxy

[sakanni]

Summary

• Adds .github/workflows/ci-versioning.yml calling the sandbox CI_Toolkit proxy
• Exercises the full proxy chain: BuroHappoldEngineeringSandbox/CI_Toolkit@main → BuroHappoldEngineeringAdmin/CI_Toolkit@feat/ci-versioning-extensibility
• Tests versioning_toolkit_repo and test_toolkit_repo inputs against sandbox forks of Versioning_Toolkit and Test_Toolkit
• Validates the FromJson.cs glob change picks up BHE_Objects.json alongside BHoM's Objects.json

What this verifies

• Versioning check runs end-to-end against sandbox BHoM_Engine
• Sandbox Versioning_Toolkit fork (with glob change) is used
• BHE_Objects.json (DatabaseConnection snapshot) is tested
• Namespace filter correctly handles BH.oM.Adapters.SQL.* types
• No false positives from unrelated BHoM types

🤖 Generated with Claude Code