fix: static_files 添加 txt 的 Content-Type 映射

src/handlers/static_files.rs

@@ -17,6 +17,7 @@ pub async fn serve_static_files(path: web::Path<String>) -> impl Responder {
                 Some("gif") => "image/gif",
                 Some("svg") => "image/svg+xml",
                 Some("webp") => "image/webp",
+                Some("txt") => "text/plain",
                 Some("css") => "text/css",
                 Some("js") => "application/javascript",
                 Some("html") => "text/html",