Add RC-006 (source code against QC-PY-001) and RC-007 (MIL-004), and
update the traceability matrix. Set lower bounds for the dev
dependencies, the one optional Fail in RC-006. Add a Gitea Actions
workflow running pytest, ruff and mypy, and describe it in the README.
Accept MIL-004 and link its Milestone in the Project Plan.
Closes#24Closes#25Closes#26Closes#27Closes#28
Task: MIL-004#1
Task: MIL-004#2
Task: MIL-004#3
Task: MIL-004#4
Task: MIL-004#5