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/MatchHud.cs

@@ -12,6 +12,8 @@ public class MatchHud : MonoBehaviour
 {
     private GUIStyle _phaseStyle;
     private GUIStyle _timeStyle;
+    private int _lastSecond = -1; // countdown text cache: OnGUI runs 2+ times per frame,
+    private string _timeText = ""; // so the string is only rebuilt when the displayed second changes
 
     private void OnGUI()
     {
@@ -20,13 +22,20 @@ public class MatchHud : MonoBehaviour
 
         EnsureStyles();
 
+        int s = Mathf.CeilToInt(Mathf.Max(0f, match.LocalPhaseRemaining));
+        if (s != _lastSecond)
+        {
+            _lastSecond = s;
+            _timeText = $"{s / 60:0}:{s % 60:00}";
+        }
+
         const float w = 360f;
         var phaseRect = new Rect((Screen.width - w) * 0.5f, 12f, w, 30f);
         var timeRect = new Rect(phaseRect.x, phaseRect.y + 28f, w, 36f);
         DrawShadowed(phaseRect, PhaseLabel(match.LocalSubPhase), _phaseStyle);
-        DrawShadowed(timeRect, FormatTime(match.LocalPhaseRemaining), _timeStyle);
+        DrawShadowed(timeRect, _timeText, _timeStyle);
 
-        if (match.LocalSubPhase == MatchManager.MatchSubPhase.Seek && LocalIsHunter())
+        if (match.LocalSubPhase == MatchManager.MatchSubPhase.Seek && NetworkPlayerSetup.LocalViewerIsHunter())
             DrawCrosshair();
     }
 
@@ -41,22 +50,6 @@ public class MatchHud : MonoBehaviour
         }
     }
 
-    private static string FormatTime(float seconds)
-    {
-        int s = Mathf.CeilToInt(Mathf.Max(0f, seconds));
-        return $"{s / 60:0}:{s % 60:00}";
-    }
-
-    private static bool LocalIsHunter()
-    {
-        var nm = Unity.Netcode.NetworkManager.Singleton;
-        if (!nm || nm.LocalClient == null) return false;
-        var po = nm.LocalClient.PlayerObject;
-        if (!po) return false;
-        var setup = po.GetComponent<NetworkPlayerSetup>();
-        return setup && setup.ScopedModes && setup.Role == PlayerRole.Hunter;
-    }
-
     private static void DrawCrosshair()
     {
         float cx = Screen.width * 0.5f;