fix: foreground sub-agents cannot use personal tool servers like Open Terminal (#31424)

With a personal tool server connection such as Open Terminal, the main model could call its tools but a foreground sub-agent it delegated to got none of them. Chats resuming after a tool approval lost those tools the same way. Setting up the tools for the main model emptied the list those later steps read from. It now works on a copy, so sub-agents and resumed chats get the same tools as the parent.

Fixes #29893

backend/open_webui/utils/middleware.py

@@ -3039,6 +3039,8 @@ async def process_chat_payload(request, form_data, user, metadata, model):
             for tool_server in direct_tool_servers:
                 if tool_server.get('is_terminal') is True and not terminal_capability:
                     continue
+                # Copy so the pops below keep metadata intact for sub-agents and approval resumes
+                tool_server = dict(tool_server)
                 system_prompt = tool_server.pop('system_prompt', None)
                 if system_prompt:
                     form_data['messages'] = add_or_update_system_message(