Write onboarding docs for a new teammate

Someone starts Monday and the setup knowledge lives in three people's heads.

Write onboarding documentation for an engineer joining this team, based on the material below.

Cover, in this order:
1. **Day one**: accounts, access, tools, and the exact commands to get the project running locally. Every prerequisite stated, no step assuming prior context.
2. **The map**: the three or four systems that matter, what each does, and how a request flows through them. One paragraph each.
3. **How we work**: branching, review, testing, deploying, and what happens when something breaks.
4. **First task**: a specific, small, genuinely useful change they can ship in week one.
5. **Where things live**: dashboards, logs, secrets, design docs, the channel to ask in.
6. **Folklore**: the unwritten rules, the parts of the codebase everyone avoids, the recurring gotcha.

Mark every step that is likely to fail and what to do when it does. Flag anything you could not answer from the material as a question for the team.

Material:

Getting someone started. READMEs, setup guides, onboarding and glossaries for the person meeting this for the first time.