feat(copy): recover HTTP 402 by error code

get-started/quick-start.mdx

@@ -847,9 +847,13 @@ If you encounter HTTP errors, here's what they mean:
 | `422`      | Unprocessable Entity  | Change the request values before retrying                                         |
 | `500`      | Internal Server Error | Retry later; contact support if the error continues                               |
 
-For a `402`, keep the same prompt and settings, check your balance, then add credits or choose a
-less expensive option before retrying. Use the response's structured `code` to decide how to
-recover; don't parse its human-readable `message`.
+For a `402`, use the response's structured `code`, not its human-readable `message`:
+
+- `insufficient_credits`: add credits or choose a request that fits your balance.
+- `subscription_required`: start a subscription.
+- `plan_upgrade_required`: upgrade your plan or choose settings available on your current plan.
+
+Credit packs do not unlock paid-plan models or settings. Retry only after resolving the indicated requirement.
 
 **For persistent errors:** Contact [support@magichour.ai](mailto:support@magichour.ai) with your project ID.