Create ASP.NET Core 8 API using the latest Elasticsearch client

[rseniuta]

Summary

• add a new ASP.NET Core 8 Web API project alongside the legacy application with modern dependency injection and configuration
• reimplement Elasticsearch services, controllers, and models against Elastic.Clients.Elasticsearch with System.Text.Json serialization
• introduce an integration test project that boots the new API and exercises search scenarios against an Elasticsearch 8.x cluster when available

Testing

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

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https://chatgpt.com/codex/tasks/task_e_68fff8dfb05c832ea6267c7b86d0f125