feat(engine): 新增 Python 策略引擎模块

- config/settings.py：Pydantic 解析 env.yaml
- data/db.py：asyncpg 连接池管理
- data/reader.py：KlineReader 只读查询 TimescaleDB
- data/models.py：KlineRecord 等 Pydantic 模型，镜像 TypeORM 实体
- example/test_db.py：数据库查询验证示例
- README.md：引擎架构文档

engine/pyproject.toml

@@ -0,0 +1,14 @@
+[project]
+name = "trade-engine"
+version = "0.1.0"
+description = "量化交易策略引擎"
+requires-python = ">=3.10"
+dependencies = [
+    "asyncpg>=0.29",
+    "pydantic>=2.5",
+    "pyyaml>=6.0",
+]
+
+[tool.pyright]
+venvPath = "."
+venv = ".venv"