fix: add cross-day dedupe

ai_daily_report/config.py

@@ -17,3 +17,12 @@ def load_source_configs(path: Path) -> list[SourceConfig]:
     if not isinstance(raw, list):
         raise ValueError("sources config must be a list")
     return [_source_config_from_dict(item) for item in raw]
+
+
+def load_pipeline_config(path: Path) -> dict[str, Any]:
+    if not path.exists():
+        return {}
+    raw = load_json(path)
+    if not isinstance(raw, dict):
+        raise ValueError("pipeline config must be an object")
+    return raw