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/FirstPersonMode.cs

@@ -14,18 +14,9 @@ public class FirstPersonMode : GameMode
     public override void Enter()
     {
         // Player stays fully controllable; only the view changes.
-        if (Manager.Player)
-        {
-            Manager.Player.enabled = true;
-            Manager.Player.ControlEnabled = true;
-        }
-
-        if (Manager.Painter)
-            Manager.Painter.PaintingEnabled = false;
-
-        // The orbit rig would otherwise keep grabbing the cursor and reading the mouse every frame.
-        if (Manager.CameraInput)
-            Manager.CameraInput.enabled = false;
+        SetPlayerControl(true);
+        SetPainting(false);
+        SetOrbitInputEnabled(false);
 
         if (Manager.FirstPerson)
             Manager.FirstPerson.SetActive(true);
@@ -38,9 +29,9 @@ public class FirstPersonMode : GameMode
         if (Manager.FirstPerson)
             Manager.FirstPerson.SetActive(false);
 
+        SetOrbitInputEnabled(true);
         if (Manager.CameraInput)
         {
-            Manager.CameraInput.enabled = true;
             // Carry the first-person facing into the orbit camera so the next orbit mode (Paint / Player
             // Control) keeps the current view angle instead of snapping back to the orbit's last-used angle.
             // Camera.main still shows the first-person view this frame (the brain hasn't blended yet).
@@ -94,7 +85,7 @@ public class FirstPersonMode : GameMode
         for (int i = 0; i < count; i++)
         {
             var netObj = _hits[i].collider.GetComponentInParent<NetworkObject>();
-            if (netObj && self && netObj == self) continue; // ignore our own collider
+            if (netObj && self && netObj == self) continue;
             if (!netObj || !netObj.IsPlayerObject) return;   // first solid hit is world geometry -> blocked
 
             var setup = netObj.GetComponent<NetworkPlayerSetup>();