docs: Add resume project introduction

[google-labs-jules]

Added doc/resume_project_intro.md to provide a structured introduction to the project's architecture and SDK design. This document is tailored for use in resumes or portfolios, highlighting key features such as the LMAX-inspired matching engine, WAL-First persistence, and the layered SDK design strategy.

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PR created automatically by Jules for task 2700155809529645558 started by @vincentf13

[google-labs-jules]

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