Document code review automation platform setup guides

[ulises-jeremias]

Summary

Create or update public documentation explaining how to configure code review
automation platforms such as Qodo Merge, gitStream, CodeRabbit, and similar
tools.

This issue follows up on #229. That PR contains useful research and examples,
but it added active repository-level configuration files. The intended
contribution is documentation-first: explain how teams can configure these
tools in their own projects without enabling those integrations directly in
this reference repository.

Recommended approach

There are two valid ways to do this contribution:

1. Update the existing guide:

   • examples/the-ultimate-guide-to-code-review-tools/README.md
   • Add or expand sections for Qodo Merge, gitStream, CodeRabbit, and any
     other relevant tools.
   • Include setup steps, prerequisites, strengths, limitations, and sample
     configuration snippets.

2. Create one or more new guides and link them from the existing guide:

   • Add new documentation under examples/, for example a dedicated guide for
     configuring code review automation platforms.
   • Link the new guide from
     examples/the-ultimate-guide-to-code-review-tools/README.md.
   • Add the new guide to the root README.md table if it should be discoverable
     from the main catalog.

References

Use these existing guides as style and structure references:

• examples/the-ultimate-guide-to-code-review-tools/README.md
• examples/the-ultimate-guide-to-pull-requests-and-code-reviews/README.md
• examples/github-actions-with-dangerjs/README.md
• examples/the-ultimate-guide-to-security-assessment-tools/README.md
• examples/the-ultimate-guide-to-security-assessment-tools/CONTINUOUS_INTEGRATION_WITH_GITHUB.md

Scope

• Document how each platform is configured.
• Include sample YAML/config snippets as documentation examples.
• Explain required accounts, tokens, GitHub App installation steps, or secrets as
  prerequisites for the reader's own project.
• Compare when each tool is useful and what tradeoffs it has.
• Reuse useful research or examples from Update code review guide #229 where appropriate.

Out of scope

• Do not add active config files for these platforms to this repository.
• Do not add repository-level workflows that run gitStream, CodeRabbit, Qodo
  Merge, or similar services in this repository.
• Do not add personal account configuration, organization-specific credentials,
  or private setup details.

Acceptance criteria

• The contribution is documentation-focused.
• The existing code review tools guide is updated or links to the new guide.
• Any sample configs are clearly presented as examples, not active repo
  configuration.
• No new active workflow/config file is added for external review platforms.
• The root README.md catalog is updated if a new guide is added.
• Public documentation does not include secrets, private links, or personal
  account setup.

Validation

• Markdown renders correctly.
• Links to related guides work.
• Any sample snippets are syntactically clear and marked as examples.