Python: Docs: Fix broken external links in Python samples and docs

[Shxiao (Shxiao101)]

Motivation & Context

A link check found 11 dead external URLs (12 occurrences) in 3 files — all verified to return 404, concentrated in the Foundry hosted-agents toolbox sample, the ChatKit package README, and one ADR. Every replacement URL was verified to return 200 before submission. Fixes #8089.

Description & Review Guide

• What are the major changes?
  • python/samples/04-hosting/foundry-hosted-agents/responses/foundry_toolbox/README.md: the azure-ai-projects toolbox CRUD sample moved from samples/hosted_agents/ to samples/toolboxes/; SUPPORTED_TOOLBOX_SCENARIOS.md became a directory of per-scenario guides, so the five auth-scenario anchors now map 1:1 to tools/mcp-unauthenticated.md, tools/mcp-key-auth.md, tools/mcp-oauth-managed.md, tools/mcp-microsoft-entra.md, and tools/mcp-user-entra-token.md (plus the index README.md); the two GitHub Copilot for Azure skill references moved from plugin/skills/... to plugins/azure-skills/skills/..., with toolbox-reference.md consolidated into toolbox/toolbox.md.
  • python/packages/chatkit/README.md: the Agent SDK integration section of docs/server.md now lives in docs/quickstart.md#generate-model-responses (same helpers, including stream_agent_response).
  • docs/decisions/0033-feature-usage-bitmask-user-agent.md: google-api-core moved into the googleapis/google-cloud-python monorepo, so the client_info.py prior-art citation points there now.
• What is the impact of these changes? Docs-only; no code behavior changes.
• What do you want reviewers to focus on? Whether the five scenario-guide replacements preserve the original per-auth-method mapping, and whether toolbox/toolbox.md is the right consolidation target for the old toolbox-reference.md.

Related Issue

Fixes #8089

Contribution Checklist

• The code builds clean without any errors or warnings
• All unit tests pass, and I have added new tests where possible (n/a — docs-only change)
• The PR follows the Contribution Guidelines
• This PR is linked to an issue and there is no other open PR for this issue (see Related Issue above).
• This is not a breaking change. If it is a breaking change, add the breaking change label (or add "[BREAKING]" to the title prefix, before or after any language prefix) — a workflow keeps the label and title prefix in sync automatically.

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Prepared with AI coding assistance; all links were individually verified (404 → 200) and the change reviewed by me.

[Copilot]

🔵 Needs a closer look

Correct the Toolbox target description so it does not promise guidance absent from that page.

Pull request overview

Fixes broken external links across Python samples, ChatKit documentation, and an ADR.

Changes:

• Updates relocated Foundry Toolbox resources and authentication guides.
• Redirects the ChatKit integration guide.
• Updates the Google API Core source citation.

File summaries

File	Description
python/samples/04-hosting/foundry-hosted-agents/responses/foundry_toolbox/README.md	Updates moved Toolbox resources and guides.
python/packages/chatkit/README.md	Updates the ChatKit integration link.
docs/decisions/0033-feature-usage-bitmask-user-agent.md	Updates the Google API Core citation.

Review details

Suppressed comments (1)

python/samples/04-hosting/foundry-hosted-agents/responses/foundry_toolbox/README.md:134

• The new toolbox.md target does not contain the OAuth consent or citation guidance attributed to it; those details are in the separate use-toolbox-in-hosted-agent.md page linked below. Please describe this target as the conceptual/schema reference so readers are not sent to the wrong page for the promised guidance.

> - [Toolbox reference](https://github.com/microsoft/GitHub-Copilot-for-Azure/blob/main/plugins/azure-skills/skills/microsoft-foundry/foundry-agent/toolbox/toolbox.md) — endpoint format, MCP protocol, OAuth consent handling, citation patterns, and troubleshooting.

• Files reviewed: 3/3 changed files
• Comments generated: 0
• Review effort level: Balanced

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[Shxiao (Shxiao101)]

@microsoft-github-policy-service agree

[Ricky-7-Yan]

Verified the current head independently:

• All 11 distinct replacement URLs return HTTP 200 (12 changed occurrences).
• The ChatKit target contains the Generate model responses section and documents the response-streaming integration referenced here.
• The five Foundry scenario pages match the README's no-auth, key, managed OAuth, agent identity / Microsoft Entra, and user Entra pass-through descriptions.
• The follow-up commit correctly narrows toolbox.md to its actual concept/API/schema scope while leaving integration guidance on the dedicated hosted-agent page.

No blocking issues found in the current diff.