docs: update README and TOOLSET documentation for Remote MCP Server m…

[danhellem]

This pull request updates the README.md to streamline the messaging around the Remote MCP Server and clarify onboarding instructions. The main changes remove outdated preview information and internal-only warnings, and emphasize the official onboarding documentation for all users.

Documentation updates:

• Removed the note about the Remote MCP Server being in public preview and the related recommendation to migrate, simplifying the introduction and focusing on the migration guidance.
• Updated the "Remote MCP Server" section to point directly to the official onboarding documentation, removing the public preview announcement and the internal-only warning for Microsoft users.

GitHub issue number

N/A

Associated Risks

None

✅ PR Checklist

• I have read the contribution guidelines
• I have read the code of conduct guidelines
• Title of the pull request is clear and informative.
• 👌 Code hygiene
• 🔭 Telemetry added, updated, or N/A
• 📄 Documentation added, updated, or N/A
• 🛡️ Automated tests added, or N/A

🧪 How did you test it?

manual review of docs

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None