Improve state persistence service example

[guardrex]

Fixes #36181

Thanks @Markz878! 🚀

I'm fleshing out your brief example with a fully working, cut-'n-paste experience.

Two paragraphs are moving up because I'm introducing some new subheadings to make the distinctions among scenarios better.

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Internal previews

📄 File	🔗 Preview link
aspnetcore/blazor/state-management/prerendered-state-persistence.md	aspnetcore/blazor/state-management/prerendered-state-persistence
aspnetcore/blazor/state-management/server.md	aspnetcore/blazor/state-management/server

[Copilot]

Pull Request Overview

This PR enhances the state persistence service documentation by providing a complete, working example that developers can copy and paste. It addresses issue #36181 by expanding the previously brief service example into a comprehensive demonstration with full code snippets.

Key changes:

• Adds a complete working example for the CounterTracker service with detailed implementation
• Reorganizes content structure with new subheadings for better clarity between different persistence scenarios
• Moves explanatory paragraphs to a more logical position in the document flow

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
aspnetcore/blazor/state-management/server.md	Adds TODO comment for future API documentation updates
aspnetcore/blazor/state-management/prerendered-state-persistence.md	Expands service persistence example with complete implementation, adds new section headers, and reorganizes content for better flow

[wadepickett]

@guardrex, Looks great! I can't find any issues. Well done.

[guardrex]

Thanks Wade! 🎸