Derive Macro WitType 

#[derive(WitType)]

Mark a struct/enum as usable in a WASM plugin interface (FIDIUS-I-0023).

This is a marker derive: it emits no code. The fidius wit generator (run from build.rs) keys on the #[derive(WitType)] attribute when it parses the crate source, mapping the struct to a WIT record (named fields) or the enum to a WIT variant (unit / single-field cases) and emitting the generated↔author conversions the wasm adapter uses. The same type continues to cross the cdylib/Python boundary via serde, unchanged.

#[derive(WitType, serde::Serialize, serde::Deserialize, Clone)]
pub struct Point { pub x: i32, pub y: i32 }