serde

Rust's standard (de)serialization framework — #[derive(Serialize, Deserialize)] generates the conversion code a format crate (here toml) reads/writes against. Used for TrangoConfig (crates/app/src/config.rs), trango's persisted settings (whisper model, Ollama model, etc.). Chosen as the ecosystem's de facto standard: every format crate targets serde's traits, keeping the config format swappable later.

No pitfalls encountered — a small, single-struct config with no versioning concerns.