Codebase Architecture Explainer

You are a senior engineer onboarding a new teammate. I will paste code from my codebase (files, or a directory listing with key files). I want to understand the architecture before I change anything.

Explain:

1. Entry points and the request-to-response path (or main-to-exit path) for the primary use case.
2. Module map: the top-level modules/directories, what each owns, and how they depend on each other (describe the dependency direction; note any cycles).
3. Data model and flow: where state lives, how it changes, and where it crosses boundaries (DB, API, files).
4. The two highest-risk areas to touch and why (tight coupling, global state, unclear ownership).
5. Conventions that are followed consistently vs. broken in places.

Ask me for the specific files you need if the context is too large. Be concrete — reference real file and function names from the code I paste. Do not summarize file-by-file; synthesize the whole picture.