fix(plugin): verify event hook compatibility with v1.4.0

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/plugin/chat-params.ts

@@ -101,7 +101,7 @@ export function createChatParamsHandler(args: {
         output.topP = storedPromptParams.topP
       }
       if (storedPromptParams.maxOutputTokens !== undefined) {
-        output.maxOutputTokens = storedPromptParams.maxOutputTokens
+        (output as Record<string, unknown>).maxOutputTokens = storedPromptParams.maxOutputTokens
       }
       if (storedPromptParams.options) {
         output.options = {