refactor(backend): use async fn syntax per clippy lint

backend/src/web/mw_auth.rs

@@ -39,16 +39,14 @@ pub async fn mw_ctx_resolver(
 impl<S: Send + Sync> FromRequestParts<S> for Ctx {
     type Rejection = LoftError;
 
-    fn from_request_parts(
+    async fn from_request_parts(
         parts: &mut axum::http::request::Parts,
         _: &S,
-    ) -> impl Future<Output = Result<Self, Self::Rejection>> + Send {
-        async move {
-            parts
-                .extensions
-                .get::<Result<Ctx, LoftError>>()
-                .ok_or(LoftError::AuthFailCtxNotInRequestExt)?
-                .clone()
-        }
+    ) -> Result<Self, Self::Rejection> {
+        parts
+            .extensions
+            .get::<Result<Ctx, LoftError>>()
+            .ok_or(LoftError::AuthFailCtxNotInRequestExt)?
+            .clone()
     }
 }