[ScottishTapWater]

Summary

• Bump every package when a commit changes root-level Directory.Build.props, Directory.Build.targets, Directory.Packages.props, global.json, or NuGet.Config.
• Use the conventional commit bump with Patch as the minimum, retaining stronger package-specific bumps.
• Keep nested files under the existing directory matching behaviour. Implementation stays within the existing directory bump calculator.

Validation

• Added regression tests first and confirmed the expected failures.
• All 135 core unit tests pass, including 31 directory bump calculator cases.
• Focused formatting verification and independent production/test reviews passed.

Stacked on #26.