feat: import Excel via chat Léa, suppression nœuds VWB, fix temperature 0.1

- Chat Léa : "importe patients.xlsx" → preview → confirmation → table SQLite
  Bouton 📎 pour upload fichier, "montre les tables", "info table X"
- VWB : suppression nœuds via touche Suppr/Backspace + bouton croix rouge
- Fix : toutes les températures VLM à 0.1 (qwen3-vl bloque à 0.0)
- Fix : capture VWB avec DISPLAY=:1

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

visual_workflow_builder/frontend_v4/src/App.tsx

@@ -133,7 +133,7 @@ function App() {
       id: step.id,
       type: 'step',
       position: step.position || { x: 100, y: 100 + index * 120 },
-      data: { step },
+      data: { step, onDelete: handleDeleteStep },
     }));
 
     setNodes(newNodes);
@@ -475,10 +475,13 @@ function App() {
               onEdgesChange={onEdgesChange}
               onConnect={onConnect}
               onEdgesDelete={onEdgesDelete}
+              onNodesDelete={(deleted) => {
+                deleted.forEach((node) => handleDeleteStep(node.id));
+              }}
               onNodeClick={(_, node) => handleSelectStep(node.id)}
               onNodeDragStop={handleNodeDragStop}
               nodeTypes={nodeTypes}
-              deleteKeyCode="Delete"
+              deleteKeyCode={['Delete', 'Backspace']}
               fitView
             >
               <Controls />

visual_workflow_builder/frontend_v4/src/components/StepNode.tsx

@@ -5,7 +5,7 @@ import { ACTIONS } from '../types';
 import { getAnchorThumbnailUrl } from '../services/api';
 
 interface StepNodeProps {
-  data: { step: Step };
+  data: { step: Step; onDelete?: (id: string) => void };
   selected?: boolean;
 }
 
@@ -18,6 +18,20 @@ function StepNode({ data, selected }: StepNodeProps) {
 
   return (
     <div className={`step-node ${selected ? 'selected' : ''} ${isConditional ? 'conditional' : ''} ${isDataLoop ? 'data-loop' : ''} ${isImport ? 'data-import' : ''}`}>
+      {/* Bouton supprimer */}
+      {selected && (
+        <button
+          className="step-node-delete"
+          title="Supprimer (Suppr)"
+          onClick={(e) => {
+            e.stopPropagation();
+            data.onDelete?.(step.id);
+          }}
+        >
+          ×
+        </button>
+      )}
+
       {/* Entrée: haut */}
       <Handle
         type="target"

visual_workflow_builder/frontend_v4/src/styles.css

@@ -415,6 +415,32 @@ body {
   padding: 0.5rem;
   font-size: 12px;
   box-shadow: 0 2px 4px rgba(0,0,0,0.1);
+  position: relative;
+}
+
+.step-node-delete {
+  position: absolute;
+  top: -8px;
+  right: -8px;
+  width: 20px;
+  height: 20px;
+  border-radius: 50%;
+  background: #e53935;
+  color: white;
+  border: 2px solid white;
+  font-size: 14px;
+  line-height: 1;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 10;
+  box-shadow: 0 1px 3px rgba(0,0,0,0.3);
+}
+
+.step-node-delete:hover {
+  background: #c62828;
+  transform: scale(1.1);
 }
 
 .step-node.selected {