Migrate the backend from pip to uv

Replace requirements.txt with a uv workspace and lockfile, install the five tavolo packages from packages/* in development and non-editable in the image, and build the Docker image with uv. Move dev tools to a PEP 735 dependency group and refresh the locked dependency versions.

.dockerignore

@@ -7,11 +7,11 @@
 .env.example
 **/.venv/
 **/__pycache__/
-*.pyc
-*.pyo
-*.egg-info/
-.mypy_cache/
-.pytest_cache/
+**/*.pyc
+**/*.pyo
+**/*.egg-info/
+**/.mypy_cache/
+**/.pytest_cache/
 web/target/
 web/dist/
 server/tests/