Add typed Decodal derive support

README.md

@@ -20,6 +20,35 @@ Embedded hosts should depend on `decodal` and provide imports with a `SourceLoad
 decodal = "0.1"
 ```
 
+## Derive support
+
+For embedded Rust applications, `decodal-derive` can generate a Decodal schema and typed decoder from a Rust struct.
+
+```toml
+[dependencies]
+decodal = "0.1"
+decodal-derive = "0.1"
+```
+
+```rust
+use decodal::{DecodalDecode, DecodalSchema, Engine};
+use decodal_derive::Decodal;
+
+#[derive(Decodal)]
+struct Service {
+    name: String,
+    #[decodal(gt = 443, default = 8443)]
+    port: i64,
+    #[decodal(rename = "feature.enable", default = true)]
+    feature_enabled: bool,
+}
+```
+
+The derive implements:
+
+- `DecodalSchema`, which produces a host schema for `Engine::bind_global`
+- `DecodalDecode`, which converts materialized `Data` into the Rust struct
+
 ## CLI
 
 A standalone CLI is kept in this repository as the `decodal-cli` workspace package.