Upgrade HeroIcons library for .NET 9 auto render support

[TaylorWatson]

Summary

• retarget the HeroIcons Razor Class Library and sample app to .NET 9 with nullable reference types enabled
• embed the SVG assets and update the component logic so icons render without HTTP access, enabling Blazor InteractiveAuto compatibility
• refresh documentation to highlight the .NET 9 upgrade and correct default parameter values

Testing

• Not run (dotnet CLI is unavailable in the execution environment)

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https://chatgpt.com/codex/tasks/task_e_68e70333537483328776f9e43b7a4ce5

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Align embedded SVG names with lookup format

The project now embeds the SVGs with LogicalName constructed from %(RecursiveDir), which preserves the directory separator. That yields resource names like TailBlazor.HeroIcons.icons.outline/academic-cap.svg, but the runtime lookup in TailBlazorHeroIconBase requests TailBlazor.HeroIcons.icons.{style}.{icon}.svg (dots instead of /). As a result GetManifestResourceStream never finds any icon and the component throws the InvalidOperationException for every render. Replace the slash in %(RecursiveDir) with a dot or adjust the lookup string so the resource names match.

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