Refactor: extract shared helpers across scripts, trim remaining doc redundancy

Deduplication pass (44 extractions):
- New SmoothedLook: shared smoothed yaw/pitch look tick + view seeding
  (FirstPersonController, FreeCamController)
- New CharacterTeleport: disable-CC-around-teleport idiom (rescue,
  owner position apply, free-cam sync)
- New GeometryUtil: RescaleToUnitScale + TransformBounds (concealment
  meter/volume, skinned collider baker)
- Paint family: canonical map read/write shared between Net and
  Persistence, snapshot decode, backend stroke dispatch, RebuildBackend,
  ResolveSeed, chunked RPC send/gate/copy, CamoKnobs/HeightKnobs
  aggregates, SanitizeFileKey, NewMaskTexture, AdoptAlbedo, FindSlider
- Player/modes: GameMode SetPlayerControl/SetPainting/SetOrbitInputEnabled,
  InputUtil.GameplayKeyPressed, NearestClimbHit, ComputeXRay delegates to
  ComputeResolutionFreeze, FingerIK TryInPlaneAngle
- Match/misc: UnhookSessionCallbacks, SendEmptyNamedMessage, SwapScenes,
  RunSessionOpAsync, CovarianceEigen, CollectClusterPoints, MatchHud
  GUIStyle cache, HsvColorPicker rehook, VoxelCenter

Documentation pass: remove 6 triplicated doc blocks and 2 restating
inline comments left after the previous reduction.

Behavior-neutral; hot-path rasterizer loops intentionally untouched.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/Scripts/FirstPersonController.cs

@@ -53,12 +53,7 @@ public class FirstPersonController : MonoBehaviour
     CinemachineCamera _vcam;
     PlayerCharacterController _player;     // body whose yaw we pin to the camera while active
     PlayerPoseController _poseController; // supplies the active pose's per-pose first-person eye offset
-    float _yaw;     // look target (raw input accumulates here)
-    float _pitch;
-    float _displayYaw;   // smoothed value actually applied to the transform
-    float _displayPitch;
-    float _yawSmoothRef;
-    float _pitchSmoothRef;
+    SmoothedLook _look; // yaw/pitch accumulator + smoothing shared with the freecam
     bool _resolved;
 
     void Awake()
@@ -89,7 +84,7 @@ public class FirstPersonController : MonoBehaviour
             SyncToCurrentView();
             InputUtil.SetCursorLocked(true);
             ApplyTransform();   // place at the eye on the same frame so the blend starts from there
-            if (_player) _player.FaceYaw = _displayYaw; // body faces the camera from frame one
+            if (_player) _player.FaceYaw = _look.DisplayYaw; // body faces the camera from frame one
         }
         else
         {
@@ -105,32 +100,18 @@ public class FirstPersonController : MonoBehaviour
         // LateUpdate so the player has already moved the CameraTarget this frame.
         LookTick();
         ApplyTransform();
-        if (_player) _player.FaceYaw = _displayYaw; // keep the body's yaw locked to the camera
+        if (_player) _player.FaceYaw = _look.DisplayYaw; // keep the body's yaw locked to the camera
     }
 
     void LookTick()
     {
         Vector2 delta = InputUtil.ReadMouseDelta() * MouseSensitivity.Multiplier;
-        _yaw += delta.x * horizontalSensitivity;
-        float vs = verticalSensitivity * (invertY ? 1f : -1f);
-        _pitch = Mathf.Clamp(_pitch + delta.y * vs, -maxPitch, maxPitch);
-
-        if (lookSmoothTime > 0f)
-        {
-            // SmoothDampAngle is frame-rate-independent and wraps yaw correctly.
-            _displayYaw = Mathf.SmoothDampAngle(_displayYaw, _yaw, ref _yawSmoothRef, lookSmoothTime);
-            _displayPitch = Mathf.SmoothDampAngle(_displayPitch, _pitch, ref _pitchSmoothRef, lookSmoothTime);
-        }
-        else
-        {
-            _displayYaw = _yaw;
-            _displayPitch = _pitch;
-        }
+        _look.Tick(delta, horizontalSensitivity, verticalSensitivity, invertY, maxPitch, lookSmoothTime);
     }
 
     void ApplyTransform()
     {
-        Quaternion rot = Quaternion.Euler(_displayPitch, _displayYaw, 0f);
+        Quaternion rot = _look.Rotation;
         if (cameraTarget)
         {
             // Sit at the first-person eye anchor, then raise/lower the eye by the active pose's first-person
@@ -151,18 +132,9 @@ public class FirstPersonController : MonoBehaviour
     {
         var cam = Camera.main;
         if (cam)
-        {
-            Vector3 e = cam.transform.rotation.eulerAngles;
-            _yaw = e.y;
-            float p = e.x > 180f ? e.x - 360f : e.x;
-            _pitch = Mathf.Clamp(p, -maxPitch, maxPitch);
-        }
-
-        // Snap the smoothed state to the fresh pose so entering never lags/jumps to catch up.
-        _displayYaw = _yaw;
-        _displayPitch = _pitch;
-        _yawSmoothRef = 0f;
-        _pitchSmoothRef = 0f;
+            _look.SyncTo(cam.transform.rotation, maxPitch);
+        else
+            _look.Snap(); // no camera: keep the current angles but still snap the smoothed state
     }
 
     void SetMeshHidden(bool hidden)