Add deployment pipeline, Dockerfile, Nomad spec and tests

- Dockerfile: python:3.12-slim + gunicorn, dynamic port, BUILD_VERSION args
- punktfri.nomad: Traefik routing for punktfri.i80.dk, host volume for SQLite
- .gitea/workflows/deploy.yml: build/push to Harbor, deploy to Nomad
- Makefile: install/run/test/build targets
- tests/test_app.py: 9 pytest tests covering all routes and validation
- requirements.txt: add gunicorn
- requirements-dev.txt: pytest
- app.py: health endpoint returns version/commit info

Makefile

@@ -0,0 +1,21 @@
+VENV := .venv
+PYTHON := $(VENV)/bin/python
+PIP := $(VENV)/bin/pip
+PYTEST := $(VENV)/bin/pytest
+
+.PHONY: install run test build
+
+$(VENV)/bin/activate:
+	python3 -m venv $(VENV)
+
+install: $(VENV)/bin/activate
+	$(PIP) install --quiet -r requirements-dev.txt
+
+run: install
+	PORT=5000 $(PYTHON) app.py
+
+test: install
+	$(PYTEST) tests/ -v
+
+build:
+	docker build -t punktfri:local .