Adding ReactiveOwningComponentBase

[BekAllaev]

What kind of change does this PR introduce?
This PR adds a ReactiveOwningComponentBase<T> to the ReactiveUI.Blazor project, as requested in #3001.

What is the current behavior?
There is currently no reactive base component that combines OwningComponentBase<T> with ReactiveUI’s IViewFor<T> / activation support in ReactiveUI.Blazor.

What is the new behavior?
Blazor components can derive from ReactiveOwningComponentBase<T> to:

• use an owning DI scope via OwningComponentBase<T>,
• expose a reactive ViewModel property,
• participate in activation (ICanActivate) and automatically call StateHasChanged on INotifyPropertyChanged changes.

What might this PR break?
No breaking changes are expected. The PR only introduces a new base class and does not modify existing public APIs or behavior.

Please check if the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Other information:
Fixes #3001.

[Copilot]

Pull request overview

This PR introduces ReactiveOwningComponentBase<T> to ReactiveUI.Blazor, providing Blazor components with ownership-based dependency injection (via OwningComponentBase<T>) combined with ReactiveUI's view model binding and activation support. This addresses issue #3001 by filling a gap in the ReactiveUI.Blazor component hierarchy where no reactive base component existed for scenarios requiring scoped service ownership.

Key Changes:

• Adds new ReactiveOwningComponentBase<T> class that extends OwningComponentBase<T>
• Implements IViewFor<T>, INotifyPropertyChanged, and ICanActivate interfaces
• Provides automatic StateHasChanged calls on view model property changes
• Includes activation/deactivation lifecycle support for IActivatableViewModel

[Copilot]

The XML documentation summary says "Raises the event" but all other reactive Blazor component base classes use "Invokes the property changed event." This should be updated for consistency:

/// <summary>
/// Invokes the property changed event.
/// </summary>

Suggested change

	/// Raises the <see cref="PropertyChanged"/> event.
	/// Invokes the property changed event.

[glennawatson]

The pr comments are ai generated so like the disposed one you highlighted it could just be redundant.

[BekAllaev]

Ah, got it — thanks! I’ve fixed some of them already and also made a few other changes, such as removing the _disposedValue variable.