QueryDTO.Value being classed as "any" meant DateAttempts would be
unmarshaled as map[string]any, so a custom UnmarshalJSON checks the data
type and unmarshals into a DateAttempt if needed. mentionedUers,
referrer and time matching implemented for activity search. Also, fixed
multi-class queries (e.g. date -and- bool for last-active).
Harvey Tindall
9715f90a48