Ragdoll death: disable movement, enable physics on mesh

Pattern: custom OnDeath event → GetCharacterMovement → DisableMovement() → GetMesh → SetSimulatePhysics(bSimulate=true) → SetCollisionEnabled(NoCollision) on CapsuleComponent. Key: SetSimulatePhysics is called on the MESH component (SkeletalMeshComponent), NOT on the actor or CharacterMovementComponent. Also set collision profile: SetCollisionProfileName('Ragdoll') on the mesh.