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/GameMode/FreeCamMode.cs

@@ -1,8 +1,7 @@
 /// <summary>
-/// Free-fly camera mode. The player is frozen in place, painting is off, and a dedicated
-/// freecam (<see cref="FreeCamController"/> + its own CinemachineCamera) takes over: fly the
-/// camera through the map with WASD/Q/E and the mouse, colliding with world geometry like the
-/// player. The orbit camera input is disabled while here so it doesn't fight for the cursor.
+/// Free-fly camera mode. The player is frozen and painting is off while a dedicated freecam
+/// (<see cref="FreeCamController"/> + its own CinemachineCamera) flies through the map, colliding
+/// with world geometry. Orbit camera input is disabled so it doesn't fight for the cursor.
 /// </summary>
 public class FreeCamMode : GameMode
 {