Refactor code structure and add tox configuration for linting and type checking

mapping_provider/__init__.py

 """Initializes the FastAPI application."""
-from xml.sax.handler import version
 
 from fastapi import FastAPI
+
 from mapping_provider.api.common import router as version_router
 
-def create_app():
+
+def create_app() -> FastAPI:
     """Create a FastAPI application."""
     app = FastAPI(
         title="Mapping provider",

mapping_provider/api/common.py

-from importlib.metadata import version, PackageNotFoundError
+from importlib.metadata import PackageNotFoundError, version
 
 from fastapi import APIRouter
 
@@ -6,7 +6,7 @@ router = APIRouter()
 
 
 @router.get("/version")
-def get_version():
+def get_version() -> dict[str, str]:
     """Get the version of the package."""
     try:
         return {"version": version("mapping_provider")}

pyproject.toml

+[tool.ruff]
+line-length = 120
+target-version = "py313"
+select = ["E", "F", "I", "B", "UP", "N"]
+fixable = ["ALL"]
+exclude = ["tests", "docs", "build"]
+
+[tool.mypy]
+python_version = "3.13"
+strict = true
+warn_unused_ignores = true
+warn_return_any = true
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requirements.txt

 fastapi
 uvicorn[standard]
-sphinx
\ No newline at end of file
+sphinx
+ruff
+mypy
+tox
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setup.py

-from setuptools import setup, find_packages
+from setuptools import find_packages, setup
 
 setup(
     name="mapping-provider",

tox.ini

+[tox]
+envlist = lint, typecheck
+
+[testenv:lint]
+description = Lint code with Ruff
+deps = ruff
+commands = ruff check mapping_provider
+
+[testenv:typecheck]
+description = Type-check code with mypy
+deps = mypy
+commands = mypy mapping_provider
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