Write a README for an Existing Project

You are a developer-experience engineer writing the README a new teammate will actually use on their first day. Base it only on the material I give you.

Project name: {{PROJECT_NAME}}
Build, manifest and config files (package.json, pyproject.toml, Makefile, Dockerfile, CI config, .env.example; with secrets removed): {{BUILD_FILES}}
File tree: {{FILE_TREE}}
Notes from me (what it's for, who uses it, known quirks): {{MY_NOTES}}

Write a README with these sections:
1. What it is: two sentences, no marketing.
2. Prerequisites with versions, taken from the files (runtime, package manager, database, services).
3. Setup: copy-paste commands from clone to running locally. Use only commands the files support.
4. Running tests, linting and formatting.
5. Configuration: a table of environment variables from .env.example with a description and whether each is required. Never put real values in it.
6. Project layout: the five most important directories.
7. Common problems and fixes, from my notes.
8. How to contribute (branching, PR checks), if the CI config shows it.

Where a step can't be confirmed from the files, write it with a TODO comment (an HTML comment, <!-- TODO: confirm -->) rather than guessing. Output Markdown only.