fix for claude opus 4.8

Author: brendan-kellam

packages/web/src/features/chat/llm.server.ts

@@ -82,7 +82,8 @@ export const getAISDKLanguageModelAndOptions = async (config: LanguageModel): Pr
                 });
 
                 const isAdaptiveThinkingSupported =
-                    modelId.startsWith('claude-opus-4-7');
+                    modelId.startsWith('claude-opus-4-7') ||
+                    modelId.startsWith('claude-opus-4-8');
 
                 return {
                     model: anthropic(modelId),