cat2151/cat-repo-auditor

AI Summary: This issue proposes three distinct updates: translating the `AGENTS.md` file into Japanese, adding documentation about formatters and linters, and including a section on source code splitting based on the Single Responsibility Principle. These tasks primarily involve documentation updates, which may require some research and understanding of existing project conventions.

AI Summary: This issue requests an initial, small-scale implementation. The task involves reading the `IMPLEMENTATION_GUIDE.md` document and then applying a "start small" approach to create a foundational piece of code or setup as a first step.