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/PaintHud.cs

@@ -155,11 +155,7 @@ public partial class PaintHud : MonoBehaviour
     {
         if (!newPainter || newPainter == painter || !_panel) return;
 
-        if (painter)
-        {
-            painter.Picked -= SyncFromPainter;
-            painter.BrushSizeChanged -= SyncBrushSize;
-        }
+        UnhookPainterEvents();
         painter = newPainter;
         _camoSynced = false; // re-seed the camo sliders once this painter's material instance is ready
 
@@ -184,13 +180,13 @@ public partial class PaintHud : MonoBehaviour
         UpdateButtonStates(); // enable Save now that a painter is bound
     }
 
-    private void OnDestroy()
+    private void OnDestroy() => UnhookPainterEvents();
+
+    private void UnhookPainterEvents()
     {
-        if (painter)
-        {
-            painter.Picked -= SyncFromPainter;
-            painter.BrushSizeChanged -= SyncBrushSize;
-        }
+        if (!painter) return;
+        painter.Picked -= SyncFromPainter;
+        painter.BrushSizeChanged -= SyncBrushSize;
     }
 
     private void OnModeChanged(GameMode mode)
@@ -383,8 +379,7 @@ public partial class PaintHud : MonoBehaviour
 
     private static void SetSlider(Transform panel, string name, float value)
     {
-        var cell = FindDeep(panel, name);
-        var slider = cell ? cell.GetComponentInChildren<Slider>() : null;
+        var slider = FindSlider(panel, name, out _);
         if (!slider) return;
         var curve = slider.GetComponent<SliderCurve>();
         if (curve) curve.SetOutput(value); // inverts the value onto the handle, then fires the slider listener
@@ -470,8 +465,7 @@ public partial class PaintHud : MonoBehaviour
     {
         if (!tex) return null;
         if (_maskSprites.TryGetValue(tex, out var cached) && cached) return cached;
-        var s = Sprite.Create(tex, new Rect(0f, 0f, tex.width, tex.height), new Vector2(0.5f, 0.5f), 100f);
-        s.hideFlags = HideFlags.HideAndDontSave;
+        var s = ToSprite(tex);
         _maskSprites[tex] = s;
         return s;
     }
@@ -525,11 +519,16 @@ public partial class PaintHud : MonoBehaviour
         toggle.onValueChanged.AddListener(v => group.alpha = v ? 1f : 0.5f);
     }
 
+    /// <summary>Finds a slider cell by name and the Slider inside it (null when either is missing).</summary>
+    private static Slider FindSlider(Transform panel, string name, out Transform cell)
+    {
+        cell = FindDeep(panel, name);
+        return cell ? cell.GetComponentInChildren<Slider>() : null;
+    }
+
     private static void WireSlider(Transform panel, string name, float value, Action<float> onChanged)
     {
-        var cell = FindDeep(panel, name);
-        if (!cell) return;
-        var slider = cell.GetComponentInChildren<Slider>();
+        var slider = FindSlider(panel, name, out Transform cell);
         if (!slider) return;
         var curve = slider.GetComponent<SliderCurve>(); // optional non-linear response on the same object
         var valueRt = cell.Find("Value");