test: Unit tests for Audit Inspector endpoints

[samtrion]

User Story

As a developer maintaining Pulse.AspNetCore, I want unit tests for the Audit Inspector.

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Requirements

• Tests.Unit/AspNetCore/AuditInspectorEndpointsTests.cs:
  • All three endpoints with mocked IAuditManagement.
  • Filter parameter binding for all AuditFilter fields.
  • 404 when record not found.

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Acceptance Criteria

• All tests pass.

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Dependencies

• Requires feat: Audit Inspector Minimal API endpoints (MapAuditInspector)