Enable chain lighting from nanoBanana output nodes

- findUpstreamLightingSettings now reads lighting from both imageInput
  and upstream nanoBanana nodes, fixing broken lighting propagation
- Clicking lighting on a nanoBanana node auto-creates a downstream
  nanoBanana if none exists, connects it, applies lighting, and runs

src/components/WorkflowCanvas.tsx

@@ -1284,9 +1284,31 @@ export function WorkflowCanvas() {
           }
         }
       } else if (sourceNode.type === "nanoBanana") {
-        updateNodeData(sourceNode.id, { lighting: settings } as Partial<NanoBananaNodeData>);
+        // nanoBanana 打光：查找下游是否已有 nanoBanana 节点，没有则自动创建
+        const downstreamImageNode = edges
+          .filter((edge) => edge.source === sourceNode.id && !edge.data?.isLoop)
+          .map((edge) => nodes.find((node) => node.id === edge.target))
+          .find((node) => node?.type === "nanoBanana");
+
+        if (downstreamImageNode) {
+          updateNodeData(downstreamImageNode.id, { lighting: settings } as Partial<NanoBananaNodeData>);
           if (!isRunning) {
-          targetNodeId = sourceNode.id;
+            targetNodeId = downstreamImageNode.id;
+          }
+        } else if (!isRunning) {
+          // 没有下游 nanoBanana，自动创建一个并连接
+          const sourceW = sourceNode.measured?.width ?? 300;
+          const genX = sourceNode.position.x + sourceW + 160;
+          const genY = sourceNode.position.y;
+          const genNodeId = addNode("nanoBanana", { x: genX, y: genY });
+          updateNodeData(genNodeId, { lighting: settings } as Partial<NanoBananaNodeData>);
+          onConnect({
+            source: sourceNode.id,
+            sourceHandle: "image",
+            target: genNodeId,
+            targetHandle: "image",
+          });
+          targetNodeId = genNodeId;
         }
       }
 

src/store/execution/nanoBananaExecutor.ts

@@ -39,9 +39,18 @@ function findUpstreamLightingSettings(
     if (edge.target !== nodeId || edge.data?.isLoop) continue;
 
     const sourceNode = nodes.find((candidate) => candidate.id === edge.source);
-    if (sourceNode?.type !== "imageInput") continue;
+    if (!sourceNode) continue;
+
+    // 从 imageInput 或 nanoBanana 节点读取打光设置
+    let lighting: LightingSettings | undefined;
+    if (sourceNode.type === "imageInput") {
+      lighting = (sourceNode.data as ImageInputNodeData).lighting;
+    } else if (sourceNode.type === "nanoBanana") {
+      lighting = (sourceNode.data as NanoBananaNodeData).lighting;
+    } else {
+      continue;
+    }
 
-    const lighting = (sourceNode.data as ImageInputNodeData).lighting;
     if (lighting?.enabled) {
       return lighting;
     }