Update README behavior list

[wieslawsoltes]

Summary

• document additional Drag & Drop base classes and events
• add Roslyn scripting and ReactiveUI navigation actions

Testing

• dotnet test --no-build --verbosity minimal (fails: command not found)

[Copilot]

Pull Request Overview

This PR expands the README to document newly introduced drag-and-drop base classes, adds a Roslyn scripting action, and lists ReactiveUI navigation actions.

• Document additional Drag & Drop base classes and events
• Add ExecuteScriptAction under a new Scripting section
• Introduce ReactiveUI navigation actions (ClearNavigationStackAction, NavigateAction, NavigateBackAction, NavigateAndReset)

Comments suppressed due to low confidence (2)

README.md:747

• The class name NavigateAndReset is inconsistent with other ReactiveUI action names—consider renaming it to NavigateAndResetAction for consistency.

**NavigateAndReset**

README.md:733

• [nitpick] New scripting and ReactiveUI actions are documented but lack references to example usage or linked tests; consider adding sample code snippets or test references to guide consumers.

### Scripting