docs(cloud): raise nginx client_max_body_size for large-context payloads

nginx default 1m rejects multi-MB chat bodies (1M-token prompts) with
413 before they reach 9Router; set 128m in the documented site config.

gitbook/content/en/deployment/cloud.md

@@ -247,6 +247,10 @@ server {
     ssl_ciphers HIGH:!aNULL:!MD5;
     ssl_prefer_server_ciphers on;
 
+    # Allow large request bodies — big context windows (e.g. 1M token prompts)
+    # produce multi-MB chat payloads; nginx default is 1m and would 413 them.
+    client_max_body_size 128m;
+
     # Proxy to 9Router
     location / {
         proxy_pass http://localhost:3000;

gitbook/content/vi/deployment/cloud.md

@@ -247,6 +247,10 @@ server {
     ssl_ciphers HIGH:!aNULL:!MD5;
     ssl_prefer_server_ciphers on;
 
+    # Cho phép body lớn — prompt ngữ cảnh 1M token sinh payload vài MB;
+    # mặc định nginx là 1m và sẽ trả 413.
+    client_max_body_size 128m;
+
     # Proxy to 9Router
     location / {
         proxy_pass http://localhost:3000;