debug: add LLM output traces to diagnose blank HTML rendering issue

- Log full LLM response preview (500 chars) with has_html detection
- Log WebSocket send with message type, completeness, and content preview
- Use clone() for chunk in BotResponse to ensure accurate logging

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

src/core/bot/channels/mod.rs

@@ -70,6 +70,16 @@ impl WebChannelAdapter {
         session_id: &str,
         message: BotResponse,
     ) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+        // DEBUG: Log what's being sent to WebSocket
+        let content_preview = if message.content.len() > 200 {
+            format!("{}... ({} chars)", &message.content[..200], message.content.len())
+        } else {
+            message.content.clone()
+        };
+        debug!("[WS_SEND] session={} msg_type={:?} is_complete={} content_preview=\"{}\"",
+            session_id, message.message_type, message.is_complete, 
+            content_preview.replace('\n', "\\n"));
+
         let connections = self.connections.lock().await;
         if let Some(tx) = connections.get(session_id) {
             if let Err(e) = tx.send(message).await {

src/core/bot/mod.rs

@@ -1128,7 +1128,7 @@ impl BotOrchestrator {
                     user_id: message.user_id.clone(),
                     session_id: message.session_id.clone(),
                     channel: message.channel.clone(),
-                    content: chunk,
+                    content: chunk.clone(),
                     message_type: MessageType::BOT_RESPONSE,
                     stream_token: None,
                     is_complete: false,
@@ -1145,6 +1145,16 @@ impl BotOrchestrator {
             }
         }
 
+        // DEBUG: Log LLM output for troubleshooting HTML rendering issues
+        let has_html = full_response.contains("</") || full_response.contains("<!--");
+        let preview = if full_response.len() > 500 {
+            format!("{}... ({} chars total)", &full_response[..500], full_response.len())
+        } else {
+            full_response.clone()
+        };
+        info!("[LLM_OUTPUT] session={} has_html={} preview=\"{}\"", 
+            session_id, has_html, preview.replace('\n', "\\n"));
+
         trace!("LLM stream complete. Full response: {}", full_response);
 
         let state_for_save = self.state.clone();