🚧 Add requirements files

requirements-dev.txt

@@ -0,0 +1,14 @@
+# Development / test dependencies for wago-modbustcp-simulator.
+# Mirrors [project.optional-dependencies].dev in pyproject.toml.
+# Includes everything from requirements.txt, plus:
+#   - pytest / pytest-asyncio: test suite
+#   - pymodbus: integration tests acting as a real Modbus TCP master
+#   - debugpy: VS Code debugging setup
+#   - httpx: ASGI test client for the FastAPI Web UI
+# Fully pinned versions for reproducible installs: requirements-lock.txt.
+-r requirements.txt
+pytest>=8.0
+pytest-asyncio>=0.23
+pymodbus>=3.6
+debugpy>=1.8
+httpx>=0.27