Refactor Assets/Scripts: trim restating comments, minor structure cleanups

Sweep over 48 files (Editor/ excluded): remove comments that restate the
code, condense class summaries, fix three stale doc statements
(HsvColorPicker alpha bar, PaintHud layoutPrefab, MasterVolume
FallbackDefault). Inline two single-use wrappers (IsPointerOverUi,
BuildModes), drop an unused using, replace a magic literal with the
existing ParallaxBase constant, and convert ~10 UnityEngine.Object null
checks to the implicit-bool convention. No serialized fields, signatures,
RPC/NetworkVariable names, defaults, or #if blocks touched.

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

Assets/Scripts/Components/UI/UiPointerSurface.cs

@@ -3,10 +3,9 @@ using UnityEngine;
 using UnityEngine.EventSystems;
 
 /// <summary>
-/// Turns a pointer press/drag on a UI graphic into a normalized (x, y) position in
-/// [0,1] within its RectTransform (origin bottom-left). Added in code to the colour
-/// picker's saturation/value field and hue bar so they react to both clicking and
-/// dragging. The graphic on the same object must be a raycast target.
+/// Turns a pointer press/drag on a UI graphic into a normalized (x, y) position in [0,1] within its
+/// RectTransform (origin bottom-left). Used by the colour picker's SV field and hue bar. The graphic
+/// on the same object must be a raycast target.
 /// </summary>
 [RequireComponent(typeof(RectTransform))]
 public class UiPointerSurface : MonoBehaviour, IPointerDownHandler, IDragHandler