Feature/cookie support

[bnoffer]

This pull request introduces significant improvements to the project’s documentation, code organization, and .NET MAUI version support. It adds detailed architectural and contribution guidelines, refactors event argument classes into dedicated files, expands the ExtWebView API with cookie management methods, and upgrades the project and CI/CD pipelines to .NET 10 and MAUI 10.0.41.

Documentation and Architecture Guidelines:

• Added comprehensive architecture and contribution guides in AGENTS.md and .github/copilot-instructions.md, detailing project structure, code style, and extension patterns. [1] [2]

.NET and MAUI Version Upgrade:

• Upgraded target frameworks in ExtendedWebView.csproj and all CI/CD workflows from .NET 9/Maui 9 to .NET 10/Maui 10.0.41, ensuring compatibility with the latest .NET MAUI features. [1] [2] [3] [4]

API and Event Model Enhancements:

• Refactored all EventArgs classes (SourceChangedEventArgs, UrlChangedEventArgs, JavaScriptActionEventArgs, SetCookieRequestEventArgs, RemoveCookieRequestEventArgs, RemoveAllCookiesRequestEventArgs) into individual files under Events/, and updated their implementations to use primary constructors and file-scoped namespaces. [1] [2] [3] [4] [5] [6]
• Expanded the IExtWebView/ExtWebView API to support cookie management via new events and methods: SetCookieAsync, UpdateCookieAsync, RemoveCookieAsync, and RemoveAllCookiesAsync, following the event-driven cross-platform pattern. [1] [2]

Code Quality Improvements:

• Added XML documentation comments for all public types and members in ExtWebView and related event classes, improving maintainability and IntelliSense support. [1] [2] [3] [4] [5] [6] [7] [8]

These changes modernize the codebase, clarify extension patterns, and make it easier for contributors to add new features in a maintainable, cross-platform way.