refactor: replace dicttoxml with stdlib implementation to avoid GPL license risk

Author: ulleo

backend/pyproject.toml

@@ -39,7 +39,7 @@ dependencies = [
     "pyyaml (>=6.0.2,<7.0.0)",
     "fastapi-mcp (>=0.3.4,<0.4.0)",
     "tabulate>=0.9.0",
-    "sqlbot-xpack>=0.0.5.33,<0.0.6.0",
+    "sqlbot-xpack>=0.0.5.34,<0.0.6.0",
     "fastapi-cache2>=0.2.2",
     "sqlparse>=0.5.3",
     "redis>=6.2.0",