chore: initial commit — leaudit-platform project skeleton

17-table PostgreSQL schema with full Chinese column comments,
FastAPI project structure (admin/common/modules),
DSL rule files, and schema migration scripts.

fastapi_common/fastapi_common_web/models/__init__.py

@@ -0,0 +1,32 @@
+"""BaseModel —— 所有业务模型的抽象基类。
+
+自动提供三个公共时间字段：
+- create_time：INSERT 时由数据库写入当前时间
+- update_time：INSERT 和 UPDATE 时自动更新
+- delete_time：默认 NULL，非 NULL 表示已软删除
+"""
+
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy import DateTime, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from fastapi_common.fastapi_common_sqlalchemy.base import Base
+
+
+class BaseModel(Base):
+    """所有业务模型的抽象基类。"""
+
+    __abstract__ = True
+
+    create_time: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), comment="创建时间"
+    )
+    update_time: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), comment="更新时间"
+    )
+    delete_time: Mapped[datetime | None] = mapped_column(
+        DateTime(timezone=True), default=None, comment="软删除时间"
+    )