[SingularVector]

Summary

Add Test-IsRegistryKey to IT-ToolBox 3.2.0, porting the existing standalone function and bringing the module to 31 exported commands.

Scope

• Check literal Windows Registry key existence, including keys with no values.
• Share provider validation, key opening and missing-key handling with Test-RegistryValue.
• Preserve existing value-name checks and handle disposal.
• Update manifest, loader, README, changelog and packaging expectations.
• Add offline contract tests and Windows HKCU integration coverage.

The PowerShell 7.4+ requirement and existing exports remain unchanged. Registry commands remain Windows-only; missing keys return false, while permission and provider failures terminate. No new dependency is introduced.

Validation

• Pester tests run — 392 passed, 0 failed, 6 skipped on macOS
• Module imports successfully — including extracted archive validation
• Documentation updated where needed
• No unrelated files changed

Notes

The module archive builds successfully. Windows CI covers actual registry access; macOS contract tests use offline handles. The matching PowerShell-Functions implementation already exists and needs no changes.

This PR prepares 3.2.0 repository content; it does not create a release tag or publish the module.