feat(ui): enhance message rendering with thinking widget and session improvements

- Add ThinkingWidget component for displaying AI reasoning content in collapsible interface
- Improve session initialization by removing redundant event listener and enhancing ID extraction
- Enhance StreamMessage component to handle diverse content structures and thinking content
- Add comprehensive debug logging for better message structure understanding
- Fix cost display logic to handle both cost_usd and total_cost_usd fields
- Refactor user message rendering to support both nested and direct content structures

src/components/ClaudeCodeSession.tsx

@@ -285,16 +285,6 @@ export const ClaudeCodeSession: React.FC<ClaudeCodeSessionProps> = ({
       // Set up event listeners before executing
       console.log('[ClaudeCodeSession] Setting up event listeners...');
       
-      // Listen for the session started event to get the Claude session ID
-      const sessionStartedUnlisten = await listen<string>(`claude-session-started:*`, (event) => {
-        const eventName = event.event;
-        const sessionId = eventName.split(':')[1];
-        if (sessionId && !claudeSessionId) {
-          console.log('[ClaudeCodeSession] Received Claude session ID:', sessionId);
-          setClaudeSessionId(sessionId);
-        }
-      });
-      
       // If we already have a Claude session ID, use isolated listeners
       const eventSuffix = claudeSessionId ? `:${claudeSessionId}` : '';
       
@@ -315,14 +305,22 @@ export const ClaudeCodeSession: React.FC<ClaudeCodeSessionProps> = ({
           });
           
           // Extract session info from system init message
-          if (message.type === "system" && message.subtype === "init" && message.session_id && !extractedSessionInfo) {
+          if (message.type === "system" && message.subtype === "init" && message.session_id) {
             console.log('[ClaudeCodeSession] Extracting session info from init message');
             // Extract project ID from the project path
             const projectId = projectPath.replace(/[^a-zA-Z0-9]/g, '-');
-            setExtractedSessionInfo({
+            
-              sessionId: message.session_id,
+            // Set both claudeSessionId and extractedSessionInfo
-              projectId: projectId
+            if (!claudeSessionId) {
-            });
+              setClaudeSessionId(message.session_id);
+            }
+            
+            if (!extractedSessionInfo) {
+              setExtractedSessionInfo({
+                sessionId: message.session_id,
+                projectId: projectId
+              });
+            }
           }
         } catch (err) {
           console.error("Failed to parse message:", err, event.payload);
@@ -364,7 +362,7 @@ export const ClaudeCodeSession: React.FC<ClaudeCodeSessionProps> = ({
         }
       });
 
-      unlistenRefs.current = [sessionStartedUnlisten, outputUnlisten, errorUnlisten, completeUnlisten];
+      unlistenRefs.current = [outputUnlisten, errorUnlisten, completeUnlisten];
       
       // Add the user message immediately to the UI (after setting up listeners)
       const userMessage: ClaudeStreamMessage = {

src/components/StreamMessage.tsx

@@ -33,7 +33,8 @@ import {
   SystemReminderWidget,
   SystemInitializedWidget,
   TaskWidget,
-  LSResultWidget
+  LSResultWidget,
+  ThinkingWidget
 } from "./ToolWidgets";
 
 interface StreamMessageProps {
@@ -73,6 +74,15 @@ const StreamMessageComponent: React.FC<StreamMessageProps> = ({ message, classNa
     if (!toolId) return null;
     return toolResults.get(toolId) || null;
   };
+  
+  // Debug logging to understand message structure
+  console.log('[StreamMessage] Rendering message:', {
+    type: message.type,
+    hasMessage: !!message.message,
+    messageStructure: message.message ? Object.keys(message.message) : 'no message field',
+    fullMessage: message
+  });
+  
   try {
     // Skip rendering for meta messages that don't have meaningful content
     if (message.isMeta && !message.leafUuid && !message.summary) {
@@ -147,6 +157,19 @@ const StreamMessageComponent: React.FC<StreamMessageProps> = ({ message, classNa
                     );
                   }
                   
+                  // Thinking content - render with ThinkingWidget
+                  if (content.type === "thinking") {
+                    renderedSomething = true;
+                    return (
+                      <div key={idx}>
+                        <ThinkingWidget 
+                          thinking={content.thinking || ''} 
+                          signature={content.signature}
+                        />
+                      </div>
+                    );
+                  }
+                  
                   // Tool use - render custom widgets based on tool name
                   if (content.type === "tool_use") {
                     const toolName = content.name?.toLowerCase();
@@ -258,6 +281,7 @@ const StreamMessageComponent: React.FC<StreamMessageProps> = ({ message, classNa
                   
                   return null;
                 })}
+                
                 {msg.usage && (
                   <div className="text-xs text-muted-foreground mt-2">
                     Tokens: {msg.usage.input_tokens} in, {msg.usage.output_tokens} out
@@ -268,16 +292,18 @@ const StreamMessageComponent: React.FC<StreamMessageProps> = ({ message, classNa
           </CardContent>
         </Card>
       );
+      
       if (!renderedSomething) return null;
       return renderedCard;
     }
 
-    // User message
+    // User message - handle both nested and direct content structures
-    if (message.type === "user" && message.message) {
+    if (message.type === "user") {
       // Don't render meta messages, which are for system use
       if (message.isMeta) return null;
 
-      const msg = message.message;
+      // Handle different message structures
+      const msg = message.message || message;
       
       let renderedSomething = false;
       
@@ -288,9 +314,9 @@ const StreamMessageComponent: React.FC<StreamMessageProps> = ({ message, classNa
               <User className="h-5 w-5 text-muted-foreground mt-0.5" />
               <div className="flex-1 space-y-2 min-w-0">
                 {/* Handle content that is a simple string (e.g. from user commands) */}
-                {typeof msg.content === 'string' && (
+                {(typeof msg.content === 'string' || (msg.content && !Array.isArray(msg.content))) && (
                   (() => {
-                    const contentStr = msg.content as string;
+                    const contentStr = typeof msg.content === 'string' ? msg.content : String(msg.content);
                     if (contentStr.trim() === '') return null;
                     renderedSomething = true;
                     
@@ -316,9 +342,9 @@ const StreamMessageComponent: React.FC<StreamMessageProps> = ({ message, classNa
                     
                     // Otherwise render as plain text
                     return (
-                      <pre className="text-sm font-mono whitespace-pre-wrap text-muted-foreground">
+                      <div className="text-sm">
                         {contentStr}
-                      </pre>
+                      </div>
                     );
                   })()
                 )}
@@ -646,8 +672,8 @@ const StreamMessageComponent: React.FC<StreamMessageProps> = ({ message, classNa
                 )}
                 
                 <div className="text-xs text-muted-foreground space-y-1 mt-2">
-                  {message.cost_usd !== undefined && (
+                  {(message.cost_usd !== undefined || message.total_cost_usd !== undefined) && (
-                    <div>Cost: ${message.cost_usd.toFixed(4)} USD</div>
+                    <div>Cost: ${((message.cost_usd || message.total_cost_usd)!).toFixed(4)} USD</div>
                   )}
                   {message.duration_ms !== undefined && (
                     <div>Duration: {(message.duration_ms / 1000).toFixed(2)}s</div>

src/components/ToolWidgets.tsx

@@ -1869,3 +1869,53 @@ export const TaskWidget: React.FC<{
     </div>
   );
 };
+
+/**
+ * Widget for displaying AI thinking/reasoning content
+ * Collapsible and closed by default
+ */
+export const ThinkingWidget: React.FC<{ 
+  thinking: string;
+  signature?: string;
+}> = ({ thinking, signature }) => {
+  const [isExpanded, setIsExpanded] = useState(false);
+  
+  return (
+    <div className="rounded-lg border border-purple-500/20 bg-gradient-to-br from-purple-500/5 to-violet-500/5 overflow-hidden">
+      <button
+        onClick={() => setIsExpanded(!isExpanded)}
+        className="w-full px-4 py-3 flex items-center justify-between hover:bg-purple-500/10 transition-colors"
+      >
+        <div className="flex items-center gap-2">
+          <div className="relative">
+            <Bot className="h-4 w-4 text-purple-500" />
+            <Sparkles className="h-2.5 w-2.5 text-purple-400 absolute -top-1 -right-1 animate-pulse" />
+          </div>
+          <span className="text-sm font-medium text-purple-600 dark:text-purple-400">
+            Thinking...
+          </span>
+        </div>
+        <ChevronRight className={cn(
+          "h-4 w-4 text-purple-500 transition-transform",
+          isExpanded && "rotate-90"
+        )} />
+      </button>
+      
+      {isExpanded && (
+        <div className="px-4 pb-4 pt-2 space-y-3 border-t border-purple-500/20">
+          <div className="prose prose-sm dark:prose-invert max-w-none">
+            <pre className="text-xs font-mono text-purple-700 dark:text-purple-300 whitespace-pre-wrap bg-purple-500/5 p-3 rounded-lg">
+              {thinking}
+            </pre>
+          </div>
+          
+          {signature && (
+            <div className="text-xs text-purple-600/60 dark:text-purple-400/60 font-mono truncate">
+              Signature: {signature.slice(0, 16)}...
+            </div>
+          )}
+        </div>
+      )}
+    </div>
+  );
+};