feat: read PORT from env var, default 8080

Server/src/main.rs

@@ -20,10 +20,11 @@ async fn main() {
 
     let app = routes::build_router(state);
 
-    let addr = "0.0.0.0:8080";
-    let listener = tokio::net::TcpListener::bind(addr)
+    let port = std::env::var("PORT").unwrap_or_else(|_| "8080".to_string());
+    let addr = format!("0.0.0.0:{port}");
+    let listener = tokio::net::TcpListener::bind(&addr)
         .await
-        .expect("无法绑定 0.0.0.0:8080");
+        .unwrap_or_else(|_| panic!("无法绑定 {addr}"));
     println!("backend listening on http://{addr}");
 
     axum::serve(listener, app).await.expect("server error");