fix favicon 404s: add <link rel=icon> to all pages, nginx 204 for /favicon.ico

nginx/posterg.conf

@@ -183,6 +183,13 @@ server {
         add_header Content-Disposition "inline";
     }
 
+    # Silence favicon.ico 404s — browsers that ignore <link rel="icon"> still request this
+    location = /favicon.ico {
+        return 204;
+        access_log off;
+        log_not_found off;
+    }
+
     # Root location - try files or 404
     location / {
         try_files $uri $uri/ =404;