Python: docs: add self-hosting sample snippets

[eavanvalkenburg]

Motivation & Context

Document the self-hosting sample seams so Learn content can stay linked to runnable source examples, including the Telegram hosting sample.

Description & Review Guide

• What are the major changes? Adds named documentation snippet regions to the local Responses, workflow, and Telegram hosting samples; expands the hosting sample index.
• What is the impact of these changes? Documentation can reference focused, runnable self-hosting examples and users can discover the Telegram sample from the hosting sample index.
• What do you want reviewers to focus on? Verify the snippet boundaries preserve sample behavior and accurately represent the hosting seams.

Related Issue

N/A

Contribution Checklist

• The PR follows the Contribution Guidelines
• This is not a breaking change.

[github-actions]

Automated Code Review

Reviewers: 5 | Confidence: 86% | Result: All clear

Reviewed: Correctness, Security Reliability, Test Coverage, Failure Modes, Design Approach

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Automated review by eavanvalkenburg's agents

[Copilot]

Pull request overview

This PR adds documentation snippet regions to Python self-hosting samples (local OpenAI Responses routes, a workflow-based Responses route, and a Telegram bot sample) and updates the hosting samples index so Learn/docs can link to focused, runnable source excerpts.

Changes:

• Added named snippet markers around key “hosting seam” code paths in the local Responses, workflow Responses, and Telegram hosting samples.
• Updated the hosting samples index to include the new af-hosting self-hosting helpers section.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
python/samples/AGENTS.md	Adds af-hosting to the sample directory tree (and updates the hosting index view).
python/samples/04-hosting/README.md	Adds a new hosting option pointing to af-hosting and a corresponding “How to Choose” entry.
python/samples/04-hosting/af-hosting/local_telegram/app.py	Adds snippet boundaries around the Telegram-to-agent run + streaming + session persistence seam.
python/samples/04-hosting/af-hosting/local_responses/app.py	Adds snippet boundaries around the FastAPI /responses route implementation.
python/samples/04-hosting/af-hosting/local_responses_workflow/app.py	Adds snippet boundaries around the workflow-backed FastAPI /responses route implementation.