serve pairs from per-city index (numbeo rankings): 361 cities, up to 10/country, all 92 capitals; myanmar->yangon

add numbeo name overrides; cache now covers 88 capitals

fill numbeo cache to 85 capitals (7140 pairs)

expand numbeo cache to all-capital pairs via per-city index

serve cross-country comparisons from an offline numbeo cache

add take-home pay estimator: tax module, cited rate data, page and tests

add country→currency and capital data with offline lookups