Document supported header input formats for transport

Co-authored-by: Eric Allam <eric@trigger.dev>

Author: cursoragent

docs/tasks/streams.mdx

@@ -614,6 +614,7 @@ The default payload sent to your task is a rich, typed object that includes:
 - `triggerOptions` as an object or resolver function (sync or async)
 - `runStore` for custom reconnect-state persistence (including async stores)
 - `onTriggeredRun` callback (sync or async) to persist or observe run IDs
+- headers passed through transport can be object, `Headers`, or tuple arrays
 
 ```ts
 import type { TriggerChatRunState, TriggerChatRunStore } from "@trigger.dev/ai";

packages/ai/README.md

@@ -52,6 +52,8 @@ Use `TriggerChatTransportPayload<UIMessage>` in your task for the default rich p
 - `messages`
 - `request` (`headers`, `body`, `metadata`)
 
+Incoming `request.headers` can be supplied as a plain object, `Headers`, or tuple arrays.
+
 ```ts
 import type { TriggerChatTransportPayload } from "@trigger.dev/ai";
 import { UIMessage } from "ai";