血缘锚定法: task_type字段+迁移+三大接口写入+TreeCanvas基于task_type布局

backend/alembic/versions/a7b8c9d0e1f2_add_task_type.py

@@ -0,0 +1,24 @@
+"""add_task_type
+
+Revision ID: a7b8c9d0e1f2
+Revises: f6a7b8c9d0e1
+Create Date: 2026-08-06
+"""
+from typing import Sequence, Union
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = "a7b8c9d0e1f2"
+down_revision: Union[str, None] = "f6a7b8c9d0e1"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column("tasks", sa.Column("task_type", sa.String(20), nullable=True, comment="派生类型: TRANSFER/SPAWN/RECOVERY"))
+    # 刷老数据：parent_task_id 非空的默认为 TRANSFER
+    op.execute("UPDATE tasks SET task_type = 'TRANSFER' WHERE parent_task_id IS NOT NULL AND task_type IS NULL")
+
+
+def downgrade() -> None:
+    op.drop_column("tasks", "task_type")

backend/app/models/task.py

@@ -70,6 +70,9 @@ class Task(Base):
     is_rework: Mapped[bool] = mapped_column(
         Boolean, default=False, comment="是否为返工任务",
     )
+    task_type: Mapped[str | None] = mapped_column(
+        String(20), nullable=True, comment="任务派生类型: TRANSFER/SPAWN/RECOVERY/null=历史数据",
+    )
     remark: Mapped[str | None] = mapped_column(
         String(2000), nullable=True, comment="任务初始描述/交接备注",
     )

backend/app/schemas/task.py

@@ -131,6 +131,7 @@ class TaskResponse(BaseModel):
     status: str
     notify_parent_on_complete: bool
     is_rework: bool = False
+    task_type: str | None = None
     remark: str | None = None
     reject_reason: str | None = None
     received_at: datetime | None = None

backend/app/services/task_service.py

@@ -112,6 +112,7 @@ def _to_flat_response(task: Task) -> TaskResponse:
         status=task.status,
         notify_parent_on_complete=task.notify_parent_on_complete,
         is_rework=task.is_rework,
+        task_type=task.task_type,
         remark=task.remark,
         reject_reason=task.reject_reason,
         received_at=task.received_at,
@@ -143,6 +144,7 @@ def _to_response(task: Task) -> TaskResponse:
         status=task.status,
         notify_parent_on_complete=task.notify_parent_on_complete,
         is_rework=task.is_rework,
+        task_type=task.task_type,
         remark=task.remark,
         reject_reason=task.reject_reason,
         received_at=task.received_at,
@@ -335,6 +337,7 @@ async def recall_task(
         task_name=task.task_name,
         assignee_id=operator_id,
         status=TASK_STATUS_WIP,
+        task_type="RECOVERY",
         notify_parent_on_complete=False,
         is_rework=False,
         remark=f"撤回「{task.task_name}」后重新接手",
@@ -377,6 +380,7 @@ async def spawn_subtask(
         task_name=data.task_name,
         assignee_id=data.assignee_id,
         status=TASK_STATUS_PENDING,
+        task_type="SPAWN",
         notify_parent_on_complete=False,
         is_rework=False,
         remark=data.remark or None,
@@ -671,6 +675,7 @@ async def transfer_task(
             task_name=task_name,
             assignee_id=assignee_id,
             status=TASK_STATUS_PENDING,
+            task_type="TRANSFER",
             notify_parent_on_complete=False,
             is_rework=False,
             remark=request.note or None,