A .pqw file is what Progress Quest web's roster page downloads: base64
of one character's JSON. pqcli.pqw converts between that and Player,
keeping the generator state, so a character carries on exactly as it
would have where it came from. Saves from before 2022, which were not
UTF-8, are read as Latin-1, and upstream's two spell renames are merged
the way its loader does. Online realm fields are dropped with a
warning.
The upstream tests check both directions against the real JS: a save
made by upstream, at a task boundary or mid-task, is imported and
played on for 3000 tasks next to upstream; then the same the other way.
