Fix MCPServerStreamableHTTP closing user-provided HTTP clients with MCP SDK 1.25+#3854

eekstunt wants to merge 9 commits intopydantic:mainpydantic/pydantic-ai:mainfrom

eekstunt:fix-3745-Fix-MCPServerStreamableHTTP-closing-user-provided-HTTP-clients-with-MCP-SDK-1.25+eekstunt/pydantic-ai:fix-3745-Fix-MCPServerStreamableHTTP-closing-user-provided-HTTP-clients-with-MCP-SDK-1.25+Copy head branch name to clipboard