fix: update Cache-Control header to no-cache and remove border top footer styles

services/darkroom/src/composite_handler.rs

···
     headers.insert("Content-Type", HeaderValue::from_static("image/jpeg"));
     headers.insert(
         "Cache-Control",
-        HeaderValue::from_static("public, max-age=3600"),
+        HeaderValue::from_static("no-cache, must-revalidate"),
     );
 
     let mut response = Response::new(Body::from(screenshot));

services/darkroom/static/css/adaptive_layout.css

···
   box-sizing: border-box;
 }
 
-.footer::before {
-  content: '';
-  position: absolute;
-  top: 0;
-  left: 15px;
-  right: 15px;
-  height: 1px;
-  background-color: #e4e4e7;
-}
-
 .title {
   font-weight: 400;
   color: #212529;