Show error message on drop error (#3189)

src/scripts/app.ts

@@ -438,6 +438,7 @@ export class ComfyApp {
   #addDropHandler() {
     // Get prompt from dropped PNG or json
     document.addEventListener('drop', async (event) => {
+      try {
         event.preventDefault()
         event.stopPropagation()
 
@@ -472,6 +473,10 @@ export class ComfyApp {
             }
           }
         }
+      } catch (err: any) {
+        console.error('Unable to process dropped item:', err)
+        useToastStore().addAlert(`Unable to process dropped item: ${err}`)
+      }
     })
 
     // Always clear over node on drag leave