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/TypingGuard.cs

@@ -1,3 +1,4 @@
+using UnityEngine;
 using UnityEngine.EventSystems;
 using TMPro;
 
@@ -9,6 +10,12 @@ using TMPro;
 /// </summary>
 public static class TypingGuard
 {
+    // Consulted several times per frame by the hotkey readers; the GetComponent lookups are cached
+    // per selected GameObject (a selection change refreshes them).
+    private static GameObject _cachedGo;
+    private static TMP_InputField _cachedTmp;
+    private static UnityEngine.UI.InputField _cachedLegacy;
+
     /// <summary>A text input field is currently focused and capturing keystrokes.</summary>
     public static bool IsTyping
     {
@@ -20,11 +27,15 @@ public static class TypingGuard
             var go = es.currentSelectedGameObject;
             if (!go) return false;
 
-            var tmp = go.GetComponent<TMP_InputField>();
-            if (tmp) return tmp.isFocused;
+            if (go != _cachedGo)
+            {
+                _cachedGo = go;
+                _cachedTmp = go.GetComponent<TMP_InputField>();
+                _cachedLegacy = _cachedTmp ? null : go.GetComponent<UnityEngine.UI.InputField>();
+            }
 
-            var legacy = go.GetComponent<UnityEngine.UI.InputField>();
-            return legacy && legacy.isFocused;
+            if (_cachedTmp) return _cachedTmp.isFocused;
+            return _cachedLegacy && _cachedLegacy.isFocused;
         }
     }
 }