Transmission #027: PDD iteration checkpoint for stats, achievements, quests

Requirements clarification for the stats / achievements / quest boards POC is written up through Question 29 in .agents/planning/2026-04-22-stats-achievements-quests/idea-honing.md, and an iteration checkpoint summary lives in iteration-checkpoint.md in the same folder. Research has not started yet; next move is an explicit choice between design, more honing, or codebase research.