CMDB: foundations + data-quality developer guides Clears the documentation debt. The module had no developer guide at all despite being the most complex one; it now has three, scoped per feature like the rest of the wiki. The foundations guide covers the thing most likely to be got wrong: there are two entirely separate kinds of link (containment means ontological dependency and cascades; relationships do not), plus where the shared write rules live and what is deliberately outside them, and why delete is explicit rather than trusting FK cascades that a Verify-grown install does not have.