Changelog: Feature: Added graphapi_conanfile_loading_analysis.md, a detailed internal analysis document describing the complete call chain for loading a root consumer conanfile via GraphAPI. This includes infrastructure setup, conanfile parsing, python_requires resolution, profile application, and graph node creation.
Docs: https://github.com/conan-io/docs/pull/XXXX

• Refer to the issue that supports this Pull Request.
• If the issue has missing info, explain the purpose/use case/pain/need that covers this Pull Request.
  This document addresses the need for a comprehensive understanding of Conan's internal GraphAPI calls when loading a root consumer conanfile. It serves as a reference for developers and maintainers to understand core logic, identify optimization opportunities, and aid in debugging related issues.
• I've read the Contributing guide.
• I've followed the PEP8 style guides for Python code.
• I've opened another PR in the Conan docs repo to the develop branch, documenting this one.