some graphing updates

crates/g3-core/src/lib.rs

@@ -1232,6 +1232,9 @@ The tool will execute immediately and you'll receive the result (success or erro
             while let Some(chunk_result) = stream.next().await {
                 match chunk_result {
                     Ok(chunk) => {
+                        // Notify UI about SSE received (including pings)
+                        self.ui_writer.notify_sse_received();
+                        
                         // Store raw chunk for debugging (limit to first 20 and last 5)
                         if chunks_received < 20 || chunk.finished {
                             raw_chunks.push(format!(

crates/g3-core/src/ui_writer.rs

@@ -41,6 +41,9 @@ pub trait UiWriter: Send + Sync {
     /// Print agent response inline (for streaming)
     fn print_agent_response(&self, content: &str);
     
+    /// Notify that an SSE event was received (including pings)
+    fn notify_sse_received(&self);
+    
     /// Flush any buffered output
     fn flush(&self);
 }
@@ -62,5 +65,6 @@ impl UiWriter for NullUiWriter {
     fn print_tool_timing(&self, _duration_str: &str) {}
     fn print_agent_prompt(&self) {}
     fn print_agent_response(&self, _content: &str) {}
+    fn notify_sse_received(&self) {}
     fn flush(&self) {}
 }