Intent: eliminate Bevy relationship-hook failures when a changed Thought route retires while the shared renderer is replacing its child population. Why: both route-root retirement and effect-child replacement were deferred, so the renderer could observe an old root and queue fresh children after that root and its previous hierarchy had already been despawned. Defense: name the shared population-rebuild set, flush game-owned root reconciliation before it, and pin both zero-orphan behavior and the composition-root schedule seam. Amend thought-fluid.md so lifecycle ordering remains part of the no-second-physics contract. 👾 Generated with [Letta Code](https://letta.com) Co-Authored-By: Letta Code <noreply@letta.com>