Introduce a waypoint-based interpolation system and integrate it into the proxy actor controller. Added F4T::InterpolationSystem (header + implementation) with TimePoint, InterpolationComponent, Lerp helpers and Update() logic. Integrates per-slot InterpolationComponent into F4TProxyActorController, switches to kinematic SetPosition-based smoothing (per-frame Lerp with snap thresholds) and removes character-controller velocity injection to prevent drift; also clears waypoints on hard snaps and uses steady_clock for timing. Added a descriptor-based bulk animation write (ApplyDesiredStateToGraphDescriptorBased) in ProxyAnimationSync for efficient graph variable updates with failure logging. Also included testing and debugging docs (phase2-interpolation-testing.md and phase2-interpolation-debugging.md) and flipped some debug flags to false.
