Censorship aggregated by world region (block fractions under review)

Under review: while the block-verdict review is on, this route answers HTTP 200 with every verdict field set to unknown or null (some coverage fields may remain), a top-level review object (status under_review, verdict unknown, reason, source, and dataAsOf: the data date, or null when the source reports none or could not be read) and X-Voidly-Verdict-Review: under_review, with Cache-Control no-store. A held answer is not an outage and not a finding either way; see https://voidly.ai/data-quality#block-verdict-review. Method when not held: per continent (default) or UN sub-region (?level=subregion): countries measured, measurements, block_fraction and confirmed national blocks mapped to region. block_fraction is a measurement-composition statistic, not the share of a region's internet that is blocked. While held, block_fraction, blocking_measurements and confirmed_national_blocks are null and regions may be null; countries_measured and measurements are coverage, not blocks.