fix(upload): add client_max_body_size to nginx config and improve upload error messaging

nginx-study.qpid.pro.conf

@@ -2,6 +2,8 @@ server {
     listen 80;
     server_name study.qpid.pro;
 
+    client_max_body_size 100M;
+
     location / {
         proxy_pass http://127.0.0.1:8002;
         proxy_http_version 1.1;