Card previews were picking whichever printing happened to load first
during ingest (ORDER BY rowid over every printing, promos and foreign
versions included), so a card's default image was effectively random.
Capture the representative printing's images straight from the Oracle
Cards bulk pass instead, and prefer that over the old printings-table
guess, falling back gracefully on an older reference.db that predates
these columns.
Also add docs/printing-tracking-design.md, a design (not yet
implemented) for optionally tracking which specific printing/finish a
library or deck card is.
Garrett Mills
d3e8a8f25a