feat: Add optimization execution and live results overlay to canvas

Phase 2 - Execution Bridge:
- Update /start endpoint to fallback to generic runner when no study script exists
- Auto-detect model files (.prt, .sim) from 1_setup/model/ directory
- Pass atomizer_spec.json path to generic runner

Phase 3 - Live Monitoring & Results Overlay:
- Add ResultBadge component for displaying values on canvas nodes
- Extend schema with resultValue and isFeasible fields
- Update DesignVarNode, ObjectiveNode, ConstraintNode, ExtractorNode to show results
- Add Run/Stop buttons and Results toggle to SpecRenderer
- Poll /status endpoint every 3s and map best_trial values to nodes
- Show green/red badges for constraint feasibility

atomizer-dashboard/frontend/src/lib/canvas/schema.ts

@@ -16,6 +16,7 @@ export interface BaseNodeData {
   label: string;
   configured: boolean;
   errors?: string[];
+  resultValue?: number | string | null; // For Results Overlay
 }
 
 export interface ModelNodeData extends BaseNodeData {
@@ -105,6 +106,7 @@ export interface ConstraintNodeData extends BaseNodeData {
   name?: string;
   operator?: '<' | '<=' | '>' | '>=' | '==';
   value?: number;
+  isFeasible?: boolean; // For Results Overlay
 }
 
 export interface AlgorithmNodeData extends BaseNodeData {