Do not recommend using anonymous user, but make name optional

[timokoessler]

Because the same rate limits would apply to all unauthenticated users.

Summary by Aikido

Security Issues: 0	Quality Issues: 0	Resolved Issues: 0

⚡ Enhancements

• Relaxed user constructors to require only non-empty id, allowing empty names

🔧 Refactors

• Stopped setting anonymous defaults in sample app middleware; conditional user set

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