Status is the count per board column, carrying EVERY column this surface knows — an empty column reads 0 rather than being absent, so a caller can render the board without inventing the vocabulary. The keys are the same closed set every other operation here validates against.
Updated is when anything in this room's work last moved, in unix seconds. ABSENT when the room has no work at all: zero would read as the epoch, and a room nobody has filed anything in has no last activity rather than an infinitely old one. Total is 0 in exactly that case.