Centralize the wiki category-path normalization (separator/quote cleanup,
type-label stripping, dedup, depth cap) into a single types helper shared by
the service, repository, and taxonomy layers so stored and queried paths are
always cleaned identically and cannot drift.
Flatten category_path into fixed category_l1/l2/l3 columns (kept in sync on
write) and rewrite ListDistinctCategoryPathsByType to group, count, and
paginate directly in cross-dialect SQL, returning the page of child folders
plus the total distinct count. This removes the prior full-column scan and
in-memory pagination (whose maxPaths cap was effectively dead) and makes Total
and later pages correct.
Add the level columns + composite index to the wiki migrations and the repo
test schema, and cover the SQL grouping/counting/pagination with a new test.
wizardchen
88c10da0b0