Development guide for the async-stripe Rust crate: strongly-typed async Stripe API bindings generated from OpenAPI spec. Use when working in the async-stripe repository for: (1) Modifying the code generation system in openapi/, (2) Adding or changing Stripe API types, requests, or enums, (3) Working with the hand-written foundation crates (async-stripe-types, async-stripe-client-core, async-stripe, async-stripe-webhook), (4) Fixing codegen bugs or adding codegen features, (5) Writing tests against stripe-mock, (6) Understanding the workspace architecture and crate relationships, (7) Debugging serialization issues (serde vs miniserde), (8) Adding new webhook event types, (9) Modifying feature flags or crate assignments.