chore: P1 工程化工具链

- pyproject.toml：pytest/black/isort/mypy 统一配置
- requirements-dev.txt：测试与代码规范开发依赖
- .flake8 / .editorconfig：PEP8 与编辑器统一
- .pre-commit-config.yaml：提交前钩子
- Makefile：常用命令集
- .env.example：环境变量模板（76 键）
- tests/：pytest 骨架 + R 响应格式冒烟测试

Co-Authored-By: Claude <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,63 @@
+# ============================================================
+# DjangoAdmin Flask+EleVue 项目管理配置
+# ============================================================
+# 说明：
+#   1. 本项目为应用工程（非库），运行依赖由 requirements.txt 管理，
+#      此处不重复声明（与既有部署约定保持一致）。
+#   2. 本文件承载各开发工具（pytest/black/isort/mypy）统一配置。
+
+[project]
+name = "djangoadmin-flask-elevue"
+version = "3.0.0"
+description = "DjangoAdmin Flask+EleVue 企业数字化开发平台（后端）"
+readme = "README.md"
+requires-python = ">=3.9"
+license = {text = "Apache-2.0"}
+authors = [
+    {name = "一米阳光团队", email = "djangoadmin@126.com"},
+]
+dependencies = []
+
+# ============================================================
+# pytest
+# ============================================================
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+addopts = "-ra --strict-markers"
+python_files = ["test_*.py"]
+filterwarnings = [
+    # 存量依赖（Flask-SQLAlchemy 3.x 等）DeprecationWarning 噪音较多，暂统一忽略
+    "ignore::DeprecationWarning",
+]
+
+# ============================================================
+# black（代码格式化）
+# ============================================================
+[tool.black]
+line-length = 120
+target-version = ["py39", "py310", "py311", "py312"]
+skip-string-normalization = false
+
+# ============================================================
+# isort（import 排序）
+# ============================================================
+[tool.isort]
+profile = "black"
+line_length = 120
+skip_gitignore = true
+known_first_party = ["application", "config", "extensions", "src", "utils"]
+
+# ============================================================
+# mypy（类型检查）
+# ============================================================
+[tool.mypy]
+python_version = "3.9"
+ignore_missing_imports = true
+warn_unused_configs = true
+exclude = ["migrations/", "ui/", "static/"]
+
+# ============================================================
+# coverage（pytest-cov）
+# ============================================================
+[tool.coverage.run]
+omit = ["migrations/*", "ui/*", "static/*", "tests/*", "scripts/*"]