🔧 Fix import error: Replace singleton pattern with direct instantiation

- Remove redundant convenience functions from demand_filtering.py (34 lines removed)
- Fix optimization_config.py to use DemandFilter() directly instead of get_shared_filter_instance()
- Eliminate unnecessary singleton pattern - each call creates fresh instance
- Resolves import error: 'cannot import name get_shared_filter_instance'
- Simplify codebase while maintaining functionality
- File size reduced from 376 to 342 lines in demand_filtering.py

src/config/optimization_config.py

@@ -75,8 +75,8 @@ def get_product_list():
     """
     try:
         # Always get fresh filtered products to reflect current configs
-        from src.demand_filtering import get_shared_filter_instance
-        filter_instance = get_shared_filter_instance()
+        from src.demand_filtering import DemandFilter
+        filter_instance = DemandFilter()
         
         # Force reload data to pick up new dates/configs
         filter_instance.load_data(force_reload=True)
@@ -260,8 +260,8 @@ def get_demand_dictionary(force_reload=False):
     """
     try:
         # Always get fresh filtered demand to reflect current configs
-        from src.demand_filtering import get_shared_filter_instance
-        filter_instance = get_shared_filter_instance()
+        from src.demand_filtering import DemandFilter
+        filter_instance = DemandFilter()
         
         # Force reload data to pick up new dates/configs
         filter_instance.load_data(force_reload=True)

src/demand_filtering.py

@@ -226,7 +226,7 @@ class DemandFilter:
         if speed_data:
             included_without_speed = sum(1 for pid in included_products if pid not in speed_data)
             if included_without_speed > 0:
-                print(f"\n⚠️  DATA QUALITY WARNING: {included_without_speed} included products missing speed data (will use default 106.7 units/hour)")
+                print(f"\n⚠️  DATA QUALITY WARNING: {included_without_speed} included products missing speed data")
         
         included_without_hierarchy = sum(1 for pid in included_products if self.standalone_master_filter(pid)[0] == "unclassified")
         if included_without_hierarchy > 0:
@@ -330,40 +330,7 @@ class DemandFilter:
         }
 
 
-# Convenience functions for easy import
-def get_filtered_product_list() -> List[str]:
-    """Get list of products ready for optimization"""
-    filter_instance = DemandFilter()
-    return filter_instance.get_filtered_product_list()
-
-
-def get_filtered_demand_dictionary() -> Dict[str, int]:
-    """Get demand dictionary for products ready for optimization"""
-    filter_instance = DemandFilter()
-    return filter_instance.get_filtered_demand_dictionary()
-
-
-def get_exclusion_summary() -> Dict:
-    """Get summary of excluded products for reporting"""
-    filter_instance = DemandFilter()
-    return filter_instance.get_exclusion_summary()
-
-
-def get_complete_analysis() -> Dict:
-    """Get complete product analysis including data quality metrics"""
-    filter_instance = DemandFilter()
-    return filter_instance.get_complete_product_analysis()
-
-
-# Singleton instance for consistency across modules
-_SHARED_FILTER_INSTANCE = None
-
-def get_shared_filter_instance():
-    """Returns a shared singleton instance of DemandFilter."""
-    global _SHARED_FILTER_INSTANCE
-    if _SHARED_FILTER_INSTANCE is None:
-        _SHARED_FILTER_INSTANCE = DemandFilter()
-    return _SHARED_FILTER_INSTANCE
+# Test script when run directly
 
 if __name__ == "__main__":
     # Test the filtering