Add the framework submodule and the accepted planning documents:
Business Case, Stakeholder Analysis, Project Plan, three milestones,
review records RC-001 to RC-006 and the traceability matrix.
Set up the project skeleton for MIL-001: pyproject.toml (Python
>=3.13, no runtime dependencies, pytest/ruff/mypy as dev extra),
src/coffee_machine/constants.py, a constants consistency test,
Doxyfile and a CI workflow that runs ruff, mypy and pytest.
Task: MIL-001#1
Task: MIL-001#2
Task: MIL-001#3
Task: MIL-001#4
Task: MIL-001#5
Closes#1Closes#2Closes#3Closes#4Closes#5
