fix: respect animation priority and defer cinematic anims until model ready

[Taiyou06]

• Route play/stop animation calls through IStateMachineHandler priority slots with an auto-assigned hash-based slot per animation name, so distinct animations stack instead of replacing each other at ModelEngine's default slot
• Add an explicit priority field on AnimationSettings and the stop entries to pin a specific slot when needed; non-state-machine handlers keep the original behavior
• Apply the same routing to the cinematic segment's animation list so the inspector's Animations entries actually stack
• Queue animation calls via ModelEngineEntity.whenModelReady and flush them after activeModel is initialized, fixing the first-open cutscene race where frame-0 animations were dropped before the deferred spawn runnable fired

[Taiyou06]

bump @OmeWillem