add: PostgreSQL 支持（asyncpg 驱动，from_url/from_config + 集成测试）

pyproject.toml

@@ -4,14 +4,24 @@ requires = ["hatchling"]
 
 [project]
 name = "chongming-database"
-version = "0.1.0"
-description = "Add your description here"
+version = "0.2.0"
+description = "异步数据库封装：SQLite（aiosqlite）+ PostgreSQL（asyncpg），基于 SQLModel/SQLAlchemy"
 readme = "README.md"
 requires-python = ">=3.12"
 dependencies = [
     "aiosqlite>=0.22.1",
+    "asyncpg>=0.30",
     "sqlmodel>=0.0.39",
 ]
 
+[dependency-groups]
+dev = [
+    "pytest>=8.0",
+    "pytest-asyncio>=0.24",
+]
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"
+
 [tool.hatch.build.targets.wheel]
 packages = ["src/chongming_database"]