M1: player stand + control handoff + Cinemachine camera system

- Install Cinemachine 3.1.7
- Stand (raised platform behind north wall) with StandPoint_0/_1
- PlayerAvatar: seat-ownership drives the mode — hold a seat => teleport to your
  stand, freeze, refuse input (control transfers/locks to your tread); release =>
  teleport back, resume on-foot. Resolves the WASD overlap off one flag.
- CameraDirector on Main Camera: 4 Cinemachine vcams (AvatarFollow / RobotFollow
  / StandView / CinematicOrbit), Brain blends; V cycles; default auto-follows the
  seat flag (on-foot=Avatar, driving=Robot). Retires the old FollowCamera.
- Verified in play: claim->teleport+freeze+RobotFollow, release->return+AvatarFollow

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Packages/manifest.json

@@ -2,6 +2,7 @@
   "dependencies": {
     "com.coplaydev.unity-mcp": "https://github.com/CoplayDev/unity-mcp.git?path=/MCPForUnity#main",
     "com.unity.ai.navigation": "2.0.13",
+    "com.unity.cinemachine": "3.1.7",
     "com.unity.collab-proxy": "2.12.4",
     "com.unity.ide.rider": "3.0.38",
     "com.unity.ide.visualstudio": "2.0.26",