fix(15): pass sessionId to fetchChatHistory for session messages

The fetchChatHistory thunk needs sessionId to determine channel type:
- With sessionId: fetches 'session' channel messages
- Without sessionId: fetches 'global' channel messages

The useEffect was only passing `channel` (which is the sessionId for
session chats), but not the `sessionId` parameter. This caused the
API to fetch global chat instead of session chat, so session messages
disappeared after page reload.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

jam-ui/src/components/client/chat/JKChatMessageList.js

@@ -131,9 +131,14 @@ const JKChatMessageList = () => {
    */
   useEffect(() => {
     if (activeChannel && fetchStatus !== 'loading' && fetchStatus !== 'succeeded') {
-      dispatch(fetchChatHistory({ channel: activeChannel }));
+      // For session chat, activeChannel is the sessionId
+      // Pass sessionId so the thunk knows to fetch 'session' channel type
+      dispatch(fetchChatHistory({
+        channel: activeChannel,
+        sessionId: sessionId || activeChannel  // Use sessionId from Redux, fallback to activeChannel
+      }));
     }
-  }, [dispatch, activeChannel, fetchStatus]);
+  }, [dispatch, activeChannel, sessionId, fetchStatus]);
 
   // Loading state
   if (fetchStatus === 'loading' && messages.length === 0) {