fix: avoid opencode structured output session breakage

Replace server-enforced structured output with local JSON parsing for Git generation
Render generated commit and PR JSON responses as compact chat cards
Tighten generation prompts while preserving active session context

packages/ui/src/components/chat/message/parts/AssistantTextPart.tsx

@@ -6,6 +6,8 @@ import type { ContentChangeReason } from '@/hooks/useChatAutoFollow';
 import { useStreamingTextThrottle } from '../../hooks/useStreamingTextThrottle';
 import { resolveAssistantDisplayText, shouldRenderAssistantText } from './assistantTextVisibility';
 import { streamPerfCount, streamPerfObserve } from '@/stores/utils/streamDebug';
+import { GeneratedJsonResultCard } from './GeneratedJsonResultCard';
+import { parseGeneratedJsonResult } from './generatedJsonResult';
 
 type PartWithText = Part & { text?: string; content?: string; value?: string; time?: { start?: number; end?: number } };
 
@@ -71,6 +73,18 @@ const AssistantTextPart: React.FC<AssistantTextPartProps> = ({
         return null;
     }
 
+    const generatedResult = !isStreaming && isFinalized ? parseGeneratedJsonResult(displayTextContent) : null;
+    if (generatedResult) {
+        return (
+            <div
+                className={`group/assistant-text relative break-words ${chatRenderMode === 'live' ? 'my-1' : ''}`}
+                key={part.id || `${messageId}-text`}
+            >
+                <GeneratedJsonResultCard result={generatedResult} />
+            </div>
+        );
+    }
+
     return (
         <div
             className={`group/assistant-text relative break-words ${chatRenderMode === 'live' ? 'my-1' : ''}`}