Status: IN
Aggregation windows are finalized only by watermark advance, follow a one-directional state lifecycle (OPEN→CLOSED→FINALIZED), and provide no mechanism to update or retract emitted results — finalization is a permanent commitment.
Three properties compose into hard irreversibility: watermark-only trigger + one-way lifecycle + no retraction
Depends on (SL): watermark-drives-finalization, window-lifecycle-one-directional, no-window-merging-or-retraction