Run a four-way parser bake-off

The bake-off has three parts that you keep separate: pages generated from known content, binary checks written before any parser runs, and parsers that only write their output to disk. The scorer reads saved outputs, so you can change a check and rescore without re-parsing. The decision that matters most is to make every check binary and specific ("£1,198.40 is in the Lift maintenance row"), not an edit distance. A one-row shift in a table has a small edit distance and is a serious error.