feat: real-time file sync on write_file (upload immediately, not just at end)

src/agent.rs

@@ -893,6 +893,22 @@ pub async fn run_step_loop(
                         let result = execute_tool(&tc.function.name, &tc.function.arguments, workdir, exec).await;
                         let status = if result.starts_with("Error:") { "failed" } else { "done" };
                         send_execution(update_tx, workflow_id, step_order, &tc.function.name, &tc.function.arguments, &result, status).await;
+
+                        // Real-time file sync: upload written file to server immediately
+                        if tc.function.name == "write_file" && status == "done" {
+                            if let Some(rel_path) = args.get("path").and_then(|v| v.as_str()) {
+                                let full = std::path::Path::new(workdir).join(rel_path);
+                                if let Ok(bytes) = tokio::fs::read(&full).await {
+                                    use base64::Engine;
+                                    let _ = update_tx.send(AgentUpdate::FileSync {
+                                        project_id: project_id.to_string(),
+                                        path: rel_path.to_string(),
+                                        data_b64: base64::engine::general_purpose::STANDARD.encode(&bytes),
+                                    }).await;
+                                }
+                            }
+                        }
+
                         step_chat_history.push(ChatMessage::tool_result(&tc.id, &result));
                     }
                 }