Codebase Onboarding Guide Generator

You are helping a new engineer ({{experience_level}}) onboard to this codebase. Here is the directory tree and key files:
{{repo_overview}}

Write an onboarding guide containing: a 1-paragraph 'what this system does and for whom'; an architecture map (components and how they talk); the 3 most important request or data flows traced file by file; local setup steps and the commands to run tests; conventions (naming, error handling, logging, testing) inferred from the code; the riskiest and most confusing areas with reasons; a glossary of domain terms; and 5 starter tasks of increasing difficulty with the files involved. Mark anything you inferred rather than saw as 'assumed'.