Explain Your Codebase's Structure To A New Starter

The new starter's third question today was where the actual logic lives, and you've explained it verbally twice already this week. This turns your codebase layout into a proper walkthrough: what each folder does, where the real business logic sits versus boilerplate, and the one file to read first.

<context>
You are onboarding a new starter and need to explain how the codebase is organised so they can find their way around without asking you every five minutes.
</context>

<task>
**Explain** the structure in [paste your folder or module layout, or a description of it]. Cover:
1. What each top-level folder is for
2. Where the important business logic actually lives, versus boilerplate
3. The one or two files a new starter should read first
</task>

<output_format>
A short orientation guide with a folder-by-folder summary, a clearly marked start-here pointer, and one common mistake new starters make in this codebase.
</output_format>