:sparkles!: add async-trait dependency for WebAppExt trait

- Add `async_trait` as an optional依赖ency in pmoapp/Cargo.toml
- Enable usage of `#[async_trait]` on WebAppExt trait and its impl for Server
- Guard async-related code with `#[cfg(feature = "pmoserver")]`

Cargo.lock

@@ -3848,6 +3848,7 @@ checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 name = "pmoapp"
 version = "0.1.0"
 dependencies = [
+ "async-trait",
  "pmoserver",
  "rust-embed",
 ]

pmoapp/Cargo.toml

@@ -10,6 +10,10 @@ rust-embed = "8.5.0"
 path = "../pmoserver"
 optional = true
 
+[dependencies.async-trait]
+optional = true
+version = "0.1"
+
 [features]
 default = []
-pmoserver = ["dep:pmoserver"]
+pmoserver = ["dep:pmoserver", "dep:async-trait"]

pmoapp/src/lib.rs

@@ -237,6 +237,8 @@
 //! - [Vue.js Documentation](https://vuejs.org/)
 //! - [Vite Documentation](https://vitejs.dev/)
 
+#[cfg(feature = "pmoserver")]
+use async_trait::async_trait;
 use rust_embed::RustEmbed;
 
 /// Structure représentant l'application web embarquée.
@@ -285,6 +287,8 @@ pub struct Webapp;
 ///     }
 /// }
 /// ```
+#[cfg(feature = "pmoserver")]
+#[async_trait]
 pub trait WebAppExt {
     /// Ajoute une Single Page Application au serveur.
     ///

pmoapp/src/pmoserver_impl.rs

@@ -27,10 +27,14 @@
 //! # }
 //! ```
 
+#[cfg(feature = "pmoserver")]
+use async_trait::async_trait;
 use crate::WebAppExt;
 use pmoserver::Server;
 use rust_embed::RustEmbed;
 
+#[cfg(feature = "pmoserver")]
+#[async_trait]
 impl WebAppExt for Server {
     async fn add_webapp<W>(&mut self, path: &str)
     where