Enhance tab layout for player and stack statistics in app.py: replace column layout with tabs for improved organization and user navigation, and adjust stack statistics condition for better data handling.

app.py

@@ -1208,7 +1208,7 @@ with tab2:
                 height=1000,
                 use_container_width=True
             )
-        player_stats_col, stack_stats_col = st.columns(2)
+        player_stats_col, stack_stats_col = st.tabs(['Player Stats', 'Stack Stats'])
         with player_stats_col:
 
             player_stats = []
@@ -1315,7 +1315,7 @@ with tab2:
             )
         
         with stack_stats_col:
-            if stack_dict is not None:
+            if 'Stack' in display_frame.headers:
                 stack_stats = []
                 stack_columns = [col for col in display_frame.columns if col.startswith('Stack')]
                 for stack in stack_dict.values():