52 pages were curated twice - 104 records - because the wiki files a page under more than one category, so two phases crawled and curated it. dedupe_pages() keeps the richest copy. 202,207 -> 202,155 records.
Adds curated/CORPUS_VERSION so an install can tell that the published corpus has moved: bootstrap compares it against a constant in the code, with no network call to ask the question.
