Create a Developer Onboarding Guide

Write a complete developer onboarding guide for the following:

Project/codebase: [name and brief description]
Tech stack: [all technologies, frameworks, languages used]
Team size: [number of developers]
Work model: [remote / office / hybrid]
Typical new developer background: [junior / mid-level / senior]
Biggest onboarding pain points currently: [what takes longest or confuses people most]
Development workflow: [git flow / trunk-based / feature branches]
CI/CD pipeline: [describe briefly]
Key architectural decisions to explain: [any non-obvious choices made]

Write the complete onboarding guide:

WELCOME AND ORIENTATION:
- What the project does and why it matters
- How the codebase fits into the wider system
- Team structure and who does what
- How decisions are made
- Communication channels and norms

ENVIRONMENT SETUP:
- Prerequisites (exact versions)
- Step-by-step local setup (every command on its own line)
- Environment variables setup (what each one does)
- Database setup and seeding
- Running the application locally
- Running tests locally
- Common setup problems and solutions

CODEBASE TOUR:
- Directory structure explained
- Key files and what they do
- How data flows through the application
- The most important files to read first
- Naming conventions in use

DEVELOPMENT WORKFLOW:
- Git branching strategy
- Commit message conventions
- Pull request process
- Code review expectations
- CI/CD pipeline walkthrough

ARCHITECTURE AND PATTERNS:
- Key architectural patterns in use and why
- Anti-patterns to avoid in this codebase
- How to add a new feature end-to-end

TESTING:
- Testing philosophy
- How to run tests
- Writing new tests
- Coverage expectations

YOUR FIRST TASK:
- A recommended starter issue or task
- How to approach it step by step
- Who to ask when stuck
- How to submit your first PR

REFERENCE:
- Useful commands cheat sheet
- Glossary of project-specific terms
- Links to external docs for key dependencies
- Runbooks for common tasks