Added the field-baseline storage layer.

src/fgai/graylog_source.py

@@ -90,6 +90,7 @@ class GraylogStreamSource:
     def _event(self, record: dict[str, object]) -> LogEvent:
         fields = {str(key).lower(): str(value) for key, value in record.items() if value is not None}
         fields["fgai_stream"] = self.stream_label
+        fields["fgai_stream_id"] = self.stream
         for canonical, candidates in DEFAULT_FIELD_MAP.items():
             mapped = self.mapping.get(canonical)
             candidates = (str(mapped),) if mapped else candidates