A directory holding exactly one file adds a path level for nothing;
cordis-catalog/ keeps its folder because it holds two sibling pages
(events.md + services.md), matching config-catalog.md which was born flat.
docs/tool-catalog/tools.md -> docs/tool-catalog.md and
docs/persistence-catalog/log-events.md -> docs/persistence-catalog.md; their
generators' OUT paths and in-page relative links drop one directory level,
and every citation repo-wide (docs, RFCs, package READMEs, generator
headers) is updated. graph-atlas.md, config-catalog.md, and the doc graphs
regenerate with the new paths.
