fix: add auth headers to loadCanvas, add canvas import

app/composables/useCanvas.ts

@@ -64,14 +64,23 @@ export const useCanvas = () => {
     return { nodes, edges }
   }
 
+  const getAuthHeaders = (): Record<string, string> => {
+    const auth = useAuth()
+    const token = auth.token?.value
+    return token ? { Authorization: `Bearer ${token}` } : {}
+  }
+
   const loadCanvas = async (id: string): Promise<CanvasData> => {
-    const data = await $fetch(`/api/canvas/${id}`)
+    const data = await $fetch(`/api/canvas/${id}`, {
+      headers: getAuthHeaders()
+    })
     return parseCanvasJson(data)
   }
 
   const updateNodeState = async (nodeId: string, state: string) => {
     return await $fetch(`/api/nodes/${nodeId}`, {
       method: 'PUT',
+      headers: getAuthHeaders(),
       body: { state }
     })
   }