feat: add rate limit schema to queue

Include rate limit configuration in the queue schema to support 
traffic shaping and request throttling. This allows consumers to 
define limits and window sizes for queue processing.

Author: aquiveal

packages/core/src/v3/schemas/queues.ts

@@ -47,6 +47,16 @@ export const QueueItem = z.object({
       overriddenBy: z.string().nullable(),
     })
     .optional(),
+  /** The rate limits of the queue */
+  rateLimit: z
+    .array(
+      z.object({
+        limit: z.number(),
+        window: z.number(),
+      })
+    )
+    .nullable()
+    .optional(),
 });
 
 export type QueueItem = z.infer<typeof QueueItem>;