工艺节点树: 新增结束分支(终止)接口 + 前端🏁结束分支按钮 + WIP可无下游完结

backend/app/services/task_service.py

@@ -223,6 +223,36 @@ async def get_all_tasks(
     return TaskListResponse(tasks=all_tasks, total=len(all_tasks))
 
 
+# ============================================================
+# 核心业务 0：结束分支（终止当前节点）
+# ============================================================
+
+async def end_task(
+    db: AsyncSession, task_id: uuid.UUID, operator_id: str | None = None
+) -> TaskResponse:
+    """
+    结束当前分支：标记任务为 COMPLETED，不创建下游任务。
+    用于工序已完结、无需转交下一人的场景。
+    """
+    task = await _get_task_or_404(db, task_id)
+
+    if task.status == TASK_STATUS_COMPLETED:
+        raise HTTPException(status_code=409, detail="此分支已经结束")
+    if task.status == TASK_STATUS_PENDING:
+        raise HTTPException(status_code=409, detail="请先接收任务再结束分支")
+
+    now = get_beijing_time()
+    task.status = TASK_STATUS_COMPLETED
+    task.completed_at = now
+
+    await _create_task_log(db, task_id, action_type="end",
+        operator_id=operator_id, remark=f"分支「{task.task_name}」已终止（无下游）")
+
+    await db.commit()
+    await db.refresh(task)
+    return _to_response(task)
+
+
 # ============================================================
 # 核心业务 1：确认接收 (PENDING → WIP)
 # ============================================================