docs: add streaming config to cli-config.yaml.example and defaults

Documents the new streaming options in the example config:
- display.streaming for CLI (under display section)
- streaming.enabled + transport/interval/threshold/cursor for gateway
- Added streaming: false to load_cli_config() defaults dict

cli.py

@@ -203,6 +203,7 @@ def load_cli_config() -> Dict[str, Any]:
             "compact": False,
             "resume_display": "full",
             "show_reasoning": False,
+            "streaming": False,
             "skin": "default",
         },
         "clarify": {