Fix seed assignment for batch requests.

ai_diffusion/model.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 import asyncio
 from copy import copy
+from dataclasses import replace
 from pathlib import Path
 from enum import Enum
 from typing import Any, NamedTuple
@@ -209,8 +210,8 @@ async def enqueue_jobs(
             params.prompt = params.regions[0].prompt
 
         for i in range(count):
-            sampling.seed = sampling.seed + i * settings.batch_size
-            params.seed = sampling.seed
+            input = replace(input, sampling=replace(sampling, seed=sampling.seed + i * settings.batch_size))
+            params.seed = input.sampling.seed
             job = self.jobs.add(kind, copy(params))
             await self._enqueue_job(job, input)