Upgrade ChartJs.Blazor to .NET 9 and support Blazor auto render

[TaylorWatson]

Summary

• upgrade the component and test projects to target .NET 9 with modern dependencies
• harden the chart component initialization so it can defer JavaScript setup until interactivity is available in Blazor auto render mode

Testing

• dotnet test (fails: dotnet is not installed in the execution environment)

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https://chatgpt.com/codex/tasks/task_e_68e704c7ee9083328c45b92f2201192e

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Stop re-render loop when JS interop unavailable

When JsRuntime.SetupChart throws during prerendering or a disconnected circuit, TryInitializeChartAsync enqueues another render via QueueRenderAsync. The lambda clears _renderQueued before calling StateHasChanged, so every failed attempt immediately schedules the next render with no delay, and OnAfterRenderAsync hits the same failure again. In Blazor auto render this results in an unbounded render loop while JavaScript interop is unavailable, keeping the prerendered request alive and consuming CPU until the page becomes interactive (or indefinitely if it never does). The component should avoid calling StateHasChanged in this situation or throttle retries, because the framework will automatically re-render once interactivity is ready.

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