feat: mongodb 单后端精简分支 — Beanie 2.x + pymongo async，移除 MySQL/alembic

pyproject.toml

@@ -1,21 +1,15 @@
 [project]
 name = "fastapi-template"
 version = "0.1.0"
-description = "开箱即用的 FastAPI 模板：MySQL(SQLAlchemy2.0 async) / MongoDB(Beanie) 可切换"
+description = "FastAPI 模板（MongoDB + Beanie 单后端分支）"
 requires-python = ">=3.11"
 dependencies = [
     "fastapi>=0.115",
     "uvicorn[standard]>=0.30",
     "pydantic>=2.7",
     "pydantic-settings>=2.4",
-    # MySQL backend
-    "sqlalchemy[asyncio]>=2.0",
-    "aiomysql>=0.2.0",
-    "alembic>=1.13",
-    # MongoDB backend
     "beanie>=2.0",
     "pymongo>=4.9",
-    "cryptography>=50.0.0",
 ]
 
 [dependency-groups]
@@ -37,8 +31,6 @@ ignore = [
 ]
 
 [tool.ruff.lint.per-file-ignores]
-"alembic/env.py" = ["E402", "F401"]   # 需要先 fileConfig 再 import 应用模块
-"alembic/versions/*" = ["I001"]       # 迁移文件是自动生成物，不整理 import
 "tests/conftest.py" = ["E402"]        # 需要先设环境变量再 import app
 
 [tool.pytest.ini_options]