feat: Add HtmxorComponentResult and HtmxorHtmlRenderer

[tanczosm]

This is just a first effort so far, untested but I figured I would draft PR this before getting too deep.

• Introduced HtmxorComponentEndpointHost class to act as a root component when executing a Htmxor Component endpoint.
• Added HtmxorComponentResultExecutor
• Created HtmxorComponentResult class that renders a Razor Component.
• Implemented HtmxorComponentResultOfT class, which is a generic version of HtmxorComponentResult.

[tanczosm]

HtmlRenderer uses HtmlRootComponent, which is public. I added HtmxorHtmlRenderer and it renders components based on HtmxorRootComponent so I had to change the visibility to public as well.

It now throws the "warning CA1815: HtmxorRootComponent should override Equals" when compiling and the checks all fail, treating that as an error.

[egil]

Should this be using HtmxLayout instead if one is present?

Suggested change

	var pageLayoutType = ComponentType.GetCustomAttribute<LayoutAttribute>()?.LayoutType;
	// Since GetCustomAttributes does not guarantee the order of attributes
	// returned, having a priority allows users to define a default HtmxLayout
	// e.g. in their _Imports.razor, and then override that on a component base,
	// just as they can with the @layout directive in razor files.
	var pageLayoutType = ComponentLayoutType = componentType
	.GetCustomAttributes<HtmxLayoutAttribute>(true)
	.OrderBy(x => x.Priority)
	.LastOrDefault()
	?.LayoutType ??
	ComponentType
	.GetCustomAttribute<LayoutAttribute>()
	?.LayoutType;

[egil]

HtmlRenderer uses HtmlRootComponent, which is public. I added HtmxorHtmlRenderer and it renders components based on HtmxorRootComponent so I had to change the visibility to public as well.

Why is HtmxorHtmlRenderer needed?

[tanczosm]

@egil I believe I can encapsulate most of the functionality of the htmxor renderer with the exception of rendering the App root component markup, which a call to a component renderer would not have awareness of. Since the root component typically wraps a Router component the HtmxorComponentResult has to go another way.

To get closer I think the ideal approach would require passing a root Layout and DefaultLayout to the component result renderer. This would require duplicating the markup inside App.razor though unless App.razor uses a layout itself.

The layout approach where the App root component uses a Layout that can be shared with the HtmxorComponentResult may be the cleanest approach.

app.MapGet("/greeting", () => new HtmxorComponentResult<GreetingComponent>() {
        RootLayout = typeof(AppLayout),  // optional root layout
        DefaultLayout = typeof(MainLayout)  // optional default layout if component doesn't specify a layout via Htmx attributes or @layout
    }
);

[egil]

Isn't supporting the "full page" render path irrelevant in this scenario? Just as with HtmlComponentResult, you use it because you want to render a specific component outside of the normal rendering flow afforded to you by Blazor or Htmxor.

[tanczosm]

Isn't supporting the "full page" render path irrelevant in this scenario? Just as with HtmlComponentResult, you use it because you want to render a specific component outside of the normal rendering flow afforded to you by Blazor or Htmxor.

Most likely so. I'll stick with matching the RazorComponentResult approach.