Fix Markov simulation chart display issue

- Fix circular import issue by moving simulation_manager to app/__init__.py
- Enhance get_wealth_evolution to include inequality metrics data
- Add get_inequality_evolution method for complete chart data
- Update API to return top10_shares and capital_shares in evolution data
- Modify onSimulationComplete to fetch and populate charts with complete data
- Fix simulation threading to properly mark completion state
- Add test script to verify chart data generation

The charts now properly display simulation results by fetching complete
evolution data when simulation completes, resolving the empty diagrams issue.

app/static/js/simulation.js

@@ -651,14 +651,44 @@ function updateMetricsDisplay(data) {
 /**
  * Handle simulation completion
  */
-function onSimulationComplete(data) {
+async function onSimulationComplete(data) {
     currentSimulation.isRunning = false;
     updateUIState('complete');
     
-    window.MarkovEconomics.utils.showNotification(
-        `Simulation completed! ${data.total_snapshots} data points collected.`, 
-        'success'
-    );
+    // Fetch complete simulation data and populate charts
+    try {
+        const response = await window.MarkovEconomics.utils.apiRequest(
+            `/api/simulation/${currentSimulation.id}/data?include_evolution=true`
+        );
+        
+        if (response.evolution) {
+            // Clear and populate with complete data
+            currentSimulation.data.iterations = response.evolution.iterations;
+            currentSimulation.data.totalWealth = response.evolution.total_wealth;
+            currentSimulation.data.giniCoefficients = response.evolution.gini_coefficients;
+            currentSimulation.data.top10Share = response.evolution.top10_shares || [];
+            currentSimulation.data.capitalShare = response.evolution.capital_shares || [];
+            
+            // Update charts with complete data
+            updateCharts();
+            
+            // Update final metrics
+            if (response.latest_snapshot) {
+                updateMetricsDisplay(response.latest_snapshot);
+            }
+        }
+        
+        window.MarkovEconomics.utils.showNotification(
+            `Simulation completed! ${data.total_snapshots} data points collected.`, 
+            'success'
+        );
+    } catch (error) {
+        console.error('Failed to fetch simulation data:', error);
+        window.MarkovEconomics.utils.showNotification(
+            'Simulation completed but failed to load results', 
+            'warning'
+        );
+    }
 }
 
 /**