Per-frame controller that reads MovementInput (WASD/ZX/Shift/mouse),
drives PhysicsEngine.Resolve for collision, and tracks motion state
changes for outbound server messages + animation switching. Walk
(~4 u/s) and run (~7 u/s) speeds match AC retail. Heartbeat timer
triggers AutonomousPosition every ~200ms while moving.
5 new tests covering idle, forward, run, turn, and state-change
detection.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>