feat: open subagent sessions read-only in context panel

Adds read-only embedded chat mode without hiding permission prompts
Opens subagent sessions in the context panel instead of replacing the main chat
Fixes context panel message loading for embedded sessions

packages/ui/src/components/views/ChatView.tsx

@@ -3,12 +3,16 @@ import { ChatContainer } from '@/components/chat/ChatContainer';
 import { ChatErrorBoundary } from '@/components/chat/ChatErrorBoundary';
 import { useSessionUIStore } from '@/sync/session-ui-store';
 
-export const ChatView: React.FC = () => {
+type ChatViewProps = {
+    readOnly?: boolean;
+};
+
+export const ChatView: React.FC<ChatViewProps> = ({ readOnly = false }) => {
     const currentSessionId = useSessionUIStore((state) => state.currentSessionId);
 
     return (
         <ChatErrorBoundary sessionId={currentSessionId || undefined}>
-            <ChatContainer />
+            <ChatContainer readOnly={readOnly} />
         </ChatErrorBoundary>
     );
 };