fix(deploy): run Z API on port 3100 in production to avoid Gitea conflict

Production server binds Gitea on :3000, so token-aggregation now uses
:3100 with a dedicated production env profile and nginx upstream.

Co-authored-by: Cursor <cursoragent@cursor.com>

deploy/nginx/z-ecosystem-domains.conf

@@ -7,7 +7,7 @@ upstream z_ecosystem_frontend {
 }
 
 upstream z_ecosystem_api {
-    server 127.0.0.1:3000;
+    server 127.0.0.1:3100;
 }
 
 upstream z_ecosystem_settlement {