Add clarification that hosting APIs require framework-dependent deployments

[Copilot]

The nethost and hostfxr hosting APIs don't support self-contained deployments, but this limitation wasn't documented.

Changes

• Added IMPORTANT note under "Hosting APIs" section clarifying that these APIs only work with framework-dependent deployments
• Clarified that self-contained deployments are only supported with built-in hosts
• Provided actionable guidance for developers evaluating deployment models

The note appears immediately after the introductory paragraph in the "Hosting APIs" section, ensuring readers understand this constraint before implementing a custom host.

This pull request was created as a result of the following prompt from Copilot chat.

Add a clarification in docs/core/tutorials/netcore-hosting.md stating that the hosting APIs (nethost and hostfxr) are only supported for framework-dependent applications and cannot be used for single-file deployments. Preferably add this note under the "Hosting APIs" section. Include guidance that if users choose the single-file publishing deployment model, these native hosting APIs will not work as expected, and a framework-dependent deployment is required.

Be clear and actionable for readers evaluating their deployment models, and reference the relevant terms (framework-dependent, single-file).

Original prompt

Add a clarification in docs/core/tutorials/netcore-hosting.md stating that the hosting APIs (nethost and hostfxr) are only supported for framework-dependent applications and cannot be used for single-file deployments. Preferably add this note under the "Hosting APIs" section. Include guidance that if users choose the single-file publishing deployment model, these native hosting APIs will not work as expected, and a framework-dependent deployment is required.

Be clear and actionable for readers evaluating their deployment models, and reference the relevant terms (framework-dependent, single-file).

This pull request was created as a result of the following prompt from Copilot chat.

Add a clarification in docs/core/tutorials/netcore-hosting.md stating that the hosting APIs (nethost and hostfxr) are only supported for framework-dependent applications and cannot be used for single-file deployments. Preferably add this note under the "Hosting APIs" section. Include guidance that if users choose the single-file publishing deployment model, these native hosting APIs will not work as expected, and a framework-dependent deployment is required.

Be clear and actionable for readers evaluating their deployment models, and reference the relevant terms (framework-dependent, single-file).

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Internal previews

📄 File	🔗 Preview link
docs/core/tutorials/netcore-hosting.md	Write a custom .NET host to control the .NET runtime from your native code

[Copilot]

Pull Request Overview

This PR adds an important note to clarify that the nethost and hostfxr hosting APIs only support framework-dependent deployments and don't work with self-contained deployments.

Key Changes

• Added an IMPORTANT callout box explaining hosting API deployment model limitations.
• Provided guidance to use framework-dependent deployments for compatibility with native hosting APIs.