fix: 修复知识库唯一约束迁移兼容性

ai_knowledge_base_v2/apps/backend/alembic/versions/0008_unique_knowledge_feishu_node.py

@@ -1,14 +1,17 @@
 from __future__ import annotations
 
 from alembic import op
+import sqlalchemy as sa
 
-revision = "0008_unique_knowledge_feishu_node"
+revision = "0008_unique_kb_node"
 down_revision = "0007_knowledge_agent_rebuild"
 branch_labels = None
 depends_on = None
 
 
 def upgrade() -> None:
+    constraints = {item["name"] for item in sa.inspect(op.get_bind()).get_unique_constraints("sys_knowledge")}
+    if "uq_knowledge_feishu_node" not in constraints:
         op.create_unique_constraint(
             "uq_knowledge_feishu_node",
             "sys_knowledge",
@@ -17,4 +20,6 @@ def upgrade() -> None:
 
 
 def downgrade() -> None:
+    constraints = {item["name"] for item in sa.inspect(op.get_bind()).get_unique_constraints("sys_knowledge")}
+    if "uq_knowledge_feishu_node" in constraints:
         op.drop_constraint("uq_knowledge_feishu_node", "sys_knowledge", type_="unique")