Accept the completed full-folder migration of MultiBallChaos using the template pipeline.
- games/MultiBallChaos/** is canonical and running
- games/MultiBallChaos_next/** removed
- structure aligned with template contract
- gameplay correctly migrated
- MultiBallChaos runs from canonical
- Canvas rendering active
- No console errors
- No unrelated changes
MultiBallChaos migration complete using single BUILD pipeline.