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.Persistence.cs

@@ -73,11 +73,7 @@ public partial class PaintHud
         return Path.Combine(HudSaveDir, key + ".hudlayout");
     }
 
-    private static string SanitizeHudKey(string s)
-    {
-        foreach (char c in Path.GetInvalidFileNameChars()) s = s.Replace(c, '_');
-        return s.Replace(' ', '_');
-    }
+    private static string SanitizeHudKey(string s) => MeshPainter.SanitizeFileKey(s);
 
     [Serializable]
     private class HudState
@@ -224,27 +220,18 @@ public partial class PaintHud
                 // it - once per HUD, so a reset always returns to the genuine material default.
                 if (!_hasDefaultCamo)
                 {
-                    _defaults.camoHalfLambert = painter.CamoHalfLambert;
-                    _defaults.camoHalfLambertBrightness = painter.CamoHalfLambertBrightness;
-                    _defaults.camoSpecularDampen = painter.CamoSpecularDampen;
-                    _defaults.occlusionThreshold = painter.OcclusionThreshold;
-                    _defaults.heightNormalIntensity = painter.HeightNormalIntensity;
-                    _defaults.parallaxIntensity = painter.ParallaxIntensity;
+                    CaptureCamoDefaults();
                     _hasDefaultCamo = true;
                 }
 
                 if (_hasPendingCamo)
                 {
-                    painter.CamoHalfLambert = _pendingCamo.x;
-                    painter.CamoHalfLambertBrightness = _pendingCamo.y;
-                    painter.CamoSpecularDampen = _pendingCamo.z;
+                    painter.CamoKnobs = _pendingCamo;
                     _hasPendingCamo = false;
                 }
                 if (_hasPendingHeight)
                 {
-                    painter.OcclusionThreshold = _pendingHeight.x;
-                    painter.HeightNormalIntensity = _pendingHeight.y;
-                    painter.ParallaxIntensity = _pendingHeight.z;
+                    painter.HeightKnobs = _pendingHeight;
                     _hasPendingHeight = false;
                 }
                 SyncCamoSliders();
@@ -471,6 +458,17 @@ public partial class PaintHud
         _hasDefaults = true;
     }
 
+    /// <summary>Snapshots the live camo + height knobs into the reset defaults (caller decides _hasDefaultCamo).</summary>
+    private void CaptureCamoDefaults()
+    {
+        _defaults.camoHalfLambert = painter.CamoHalfLambert;
+        _defaults.camoHalfLambertBrightness = painter.CamoHalfLambertBrightness;
+        _defaults.camoSpecularDampen = painter.CamoSpecularDampen;
+        _defaults.occlusionThreshold = painter.OcclusionThreshold;
+        _defaults.heightNormalIntensity = painter.HeightNormalIntensity;
+        _defaults.parallaxIntensity = painter.ParallaxIntensity;
+    }
+
     /// <summary>
     /// Resets the HUD to its authored defaults, exactly as if the saved layout file had been deleted: the
     /// panels jump back to their prefab positions and every brush value returns to the painter's prefab /
@@ -494,14 +492,7 @@ public partial class PaintHud
             // Reset clicked before the ready-gate captured the camo defaults? keep the live camo rather than
             // slamming it to the not-yet-filled 0 (which would flatten the material's lighting).
             if (!_hasDefaultCamo && painter.IsReady)
-            {
-                _defaults.camoHalfLambert = painter.CamoHalfLambert;
-                _defaults.camoHalfLambertBrightness = painter.CamoHalfLambertBrightness;
-                _defaults.camoSpecularDampen = painter.CamoSpecularDampen;
-                _defaults.occlusionThreshold = painter.OcclusionThreshold;
-                _defaults.heightNormalIntensity = painter.HeightNormalIntensity;
-                _defaults.parallaxIntensity = painter.ParallaxIntensity;
-            }
+                CaptureCamoDefaults();
 
             ApplyValues(painter, _defaults);
             SyncFromPainter();