more fixes

app.py

@@ -57,9 +57,19 @@ def _empty_dataframe(message: str = "No data available") -> pd.DataFrame:
     return pd.DataFrame({"status": [message]})
 
 
+
+DEFAULT_STATE = {
+    "dataframe": None,
+    "filtered_df": None,
+    "column_types": None,
+    "filter_meta": None,
+    "source_name": None,
+}
+
+
 def _ensure_state(state) -> Dict[str, Any]:
     """Guarantee a dictionary-based state object."""
-    return state or {}
+    return state or DEFAULT_STATE.copy()
 
 
 def _current_dataframe(state, filtered: bool = True) -> pd.DataFrame:
@@ -444,7 +454,7 @@ def _describe_sample_dataset(selection: Optional[str]) -> str:
 def create_dashboard():
     with gr.Blocks(theme=gr.themes.Soft()) as demo:
         gr.Markdown("# Business Intelligence Dashboard")
-        dataset_state = gr.State({})
+        dataset_state = gr.State(DEFAULT_STATE.copy())
         last_figure_state = gr.State(None)
 
         sample_choices = list(sample_dataset_options().keys())
@@ -738,4 +748,4 @@ def create_dashboard():
 
 if __name__ == "__main__":
     demo = create_dashboard()
-    demo.launch(server_name="0.0.0.0", server_port=7860, share=True)
+    demo.launch(server_name="0.0.0.0", server_port=7860)