chore: add changeset for @trigger.dev/ai package

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

Author: cursoragent

.changeset/ai-sdk-chat-transport.md

@@ -0,0 +1,41 @@
+---
+"@trigger.dev/ai": minor
+---
+
+New package: `@trigger.dev/ai` — AI SDK integration for Trigger.dev
+
+Provides `TriggerChatTransport`, a custom `ChatTransport` implementation for the Vercel AI SDK that bridges `useChat` with Trigger.dev's durable task execution and realtime streams.
+
+**Frontend usage:**
+```tsx
+import { useChat } from "@ai-sdk/react";
+import { TriggerChatTransport } from "@trigger.dev/ai";
+
+const { messages, sendMessage } = useChat({
+  transport: new TriggerChatTransport({
+    accessToken: publicAccessToken,
+    taskId: "my-chat-task",
+  }),
+});
+```
+
+**Backend task:**
+```ts
+import { task, streams } from "@trigger.dev/sdk";
+import { streamText, convertToModelMessages } from "ai";
+import type { ChatTaskPayload } from "@trigger.dev/ai";
+
+export const myChatTask = task({
+  id: "my-chat-task",
+  run: async (payload: ChatTaskPayload) => {
+    const result = streamText({
+      model: openai("gpt-4o"),
+      messages: convertToModelMessages(payload.messages),
+    });
+    const { waitUntilComplete } = streams.pipe("chat", result.toUIMessageStream());
+    await waitUntilComplete();
+  },
+});
+```
+
+Also exports `createChatTransport()` factory function and `ChatTaskPayload` type for task-side typing.