feat(oa): add oa_instance_comment table and model

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/models/models.py

@@ -982,6 +982,28 @@ class OaInstanceEvent(Base):
     del_flag = Column(SmallInteger, nullable=False, default=0, comment="删除标记")
 
 
+class OaInstanceComment(Base):
+    """OA审批实例评论 oa_instance_comment"""
+
+    __tablename__ = "oa_instance_comment"
+
+    id = Column(String(64), primary_key=True, comment="主键ID")
+    instance_id = Column(String(64), nullable=False, comment="所属实例ID")
+    content = Column(String(1024), nullable=False, comment="评论正文")
+    attachment_refs_json = Column(Text, nullable=True, comment="引用表单附件快照 JSON")
+    status = Column(String(16), nullable=False, default="normal", comment="normal/revoked")
+    revoked_time = Column(DateTime, nullable=True, comment="撤回时间")
+    tenant_no = Column(String(64), nullable=False, default="zkxw", comment="租户编号")
+    order_num = Column(Integer, nullable=True, comment="排序号")
+    remark = Column(String(512), nullable=True, comment="备注")
+    create_by = Column(String(64), nullable=True, comment="创建人id（评论作者）")
+    create_dept_id = Column(String(64), nullable=False, default="", comment="创建人部门ID")
+    create_time = Column(DateTime, nullable=False, default=datetime.now, comment="创建时间")
+    update_by = Column(String(64), nullable=True, comment="更新人id")
+    update_time = Column(DateTime, nullable=False, default=datetime.now, onupdate=datetime.now, comment="更新时间")
+    del_flag = Column(SmallInteger, nullable=False, default=0, comment="删除标记")
+
+
 class OaRelation(Base):
     """OA关联审批 oa_relation"""