Add POI feature and imporve the overall backend implementation

services/forecasting/app/api/scenario_operations.py

@@ -434,10 +434,22 @@ async def compare_scenarios(
     Compare multiple scenario simulations
 
     **PROFESSIONAL/ENTERPRISE ONLY**
+
+    **STATUS**: Not yet implemented - requires scenario persistence layer
+
+    **Future implementation would**:
+    1. Retrieve saved scenarios by ID from database
+    2. Use ScenarioPlanner.compare_scenarios() to analyze them
+    3. Return comparison matrix with best/worst case analysis
+
+    **Prerequisites**:
+    - Scenario storage/retrieval database layer
+    - Scenario CRUD endpoints
+    - UI for scenario management
     """
-    # TODO: Implement scenario comparison
-    # This would retrieve saved scenarios and compare them
+    # NOTE: HTTP 501 Not Implemented is the correct response for unimplemented optional features
+    # The ML logic exists in scenario_planner.py but requires a persistence layer
     raise HTTPException(
         status_code=status.HTTP_501_NOT_IMPLEMENTED,
-        detail="Scenario comparison not yet implemented"
+        detail="Scenario comparison requires scenario persistence layer (future feature)"
     )