Refactor scripts: dedup remainder, remove dead code, perf hardening

Iteration 4 over Assets/Scripts (no component/file splits, no Unity assets touched):

Dedup:
- Route inline cursor-release, material guards, Ctrl-held and undo/redo
  input through existing InputUtil / SetMatFloat helpers
- Add ungated InputUtil.KeyPressedThisFrame; GameplayKeyPressed builds on it
- Unify FindDeep/FindDeepChild into GeometryUtil.FindDeep

Dead code / stale docs:
- Remove unused code-gen bake path (HsvColorPicker.Build, PaintHud factory)
- Drop unreferenced symbols (SubPhaseChanged event, LocalPhaseDuration,
  IsLocalSceneMain, MouseSensitivity.Changed, IsPaused, InSession,
  NetworkControlled, PreviousPose, JointCount, voxel-count accessors)
- Fix incorrect PlayerRole / PaintHud / Pick / PlayerPose docs

Perf / robustness (behaviour-neutral):
- ConcealmentMeter.Evaluate: reuse vertex/topology buffers, two-pointer
  crossing count
- BuildMeshCaches: alloc-free vertex copy, cached topology/UVs
- Guard all PlayerPaintSync LogSync sites behind logSync
- Cache LocalViewerIsHunter / controller / CanShoot / TypingGuard lookups;
  dedup LocalIsHunter with MatchHud
- Change-guard RefreshEmissionColor and HeroCutout.Disarm
- Cache scene/countdown string comparisons per frame
- Grow NonAlloc buffers and log-once on saturation

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Scripts/PlayerRole.cs

@@ -1,7 +1,7 @@
 /// <summary>
-/// Which side a spawned avatar plays. Picked at connect time (NetworkBootstrap) and sent as the
-/// connection-approval payload so the server spawns the matching prefab variant, then baked into
-/// that prefab and read back by GameModeManager to build the role's mode set.
+/// Which side a spawned avatar plays. Baked into each avatar prefab variant (the server rolls the
+/// roles at match start and spawns the matching variant); read back by GameModeManager to build the
+/// role's mode set.
 /// </summary>
 public enum PlayerRole
 {