fix: image reading error, also add error toast for event bus

packages/opencode/src/cli/cmd/tui/app.tsx

@@ -367,6 +367,27 @@ function App() {
     }
   })
 
+  event.on(SessionApi.Event.Error.type, (evt) => {
+    const error = evt.properties.error
+    const message = (() => {
+      if (!error) return "An error occured"
+
+      if (typeof error === "object") {
+        const data = error.data
+        if ("message" in data && typeof data.message === "string") {
+          return data.message
+        }
+      }
+      return String(error)
+    })()
+
+    toast.show({
+      variant: "error",
+      message,
+      duration: 5000,
+    })
+  })
+
   return (
     <box
       width={dimensions().width}