feat: add approve/reject buttons for wait_for_approval

- CommentSection shows explicit approve/reject buttons when waiting
- Reject aborts the workflow, approve continues with optional feedback
- Backend parses approved:/rejected: prefixes from comment content

src/agent.rs

@@ -1177,7 +1177,27 @@ async fn run_agent_loop(
                             }
                         };
 
-                        tracing::info!("[workflow {}] Approval received: {}", workflow_id, approval_content);
+                        tracing::info!("[workflow {}] Approval response: {}", workflow_id, approval_content);
+
+                        // Check if user rejected
+                        if approval_content.starts_with("rejected:") {
+                            let reason = approval_content.strip_prefix("rejected:").unwrap_or("").trim();
+                            tracing::info!("[workflow {}] User rejected: {}", workflow_id, reason);
+                            if let Some(step) = state.steps.iter_mut().find(|s| s.order == cur) {
+                                step.status = StepStatus::Failed;
+                                step.user_feedbacks.push(format!("用户终止: {}", reason));
+                            }
+                            log_execution(pool, broadcast_tx, workflow_id, cur, "wait_for_approval", "rejected", reason, "failed").await;
+                            // Return error to end the agent loop; caller sets workflow to "failed"
+                            return Err(anyhow::anyhow!("用户终止了执行: {}", reason));
+                        }
+
+                        // Approved — extract feedback after "approved:" prefix if present
+                        let feedback = if approval_content.starts_with("approved:") {
+                            approval_content.strip_prefix("approved:").unwrap_or("").trim().to_string()
+                        } else {
+                            approval_content.clone()
+                        };
 
                         // Resume: restore Running status
                         if let Some(step) = state.steps.iter_mut().find(|s| s.order == cur) {
@@ -1197,8 +1217,13 @@ async fn run_agent_loop(
                             steps: plan_infos_from_state(&state),
                         });
 
+                        let tool_msg = if feedback.is_empty() {
+                            "用户已确认，继续执行。".to_string()
+                        } else {
+                            format!("用户已确认。反馈: {}", feedback)
+                        };
                         state.current_step_chat_history.push(
-                            ChatMessage::tool_result(&tc.id, &format!("用户已确认。反馈: {}", approval_content))
+                            ChatMessage::tool_result(&tc.id, &tool_msg)
                         );
                     }