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/MeshPainter.Backend.cs

@@ -90,25 +90,20 @@ public partial class MeshPainter
 
     private static bool MapIsLinear(int mi) => mi == MAP_MSO;
 
-    private string[] MapProps(int mi)
+    // Material slots per map, as pre-hashed IDs (this runs per stroke end - no per-call allocations).
+    // MSO: one mask map drives three URP slots: _MetallicGlossMap (R/A) + _OcclusionMap (G) +
+    // _ParallaxMap (G = occlusion reused as a 0.5-centred height for parallax/relief).
+    private static readonly int[][] MapPropIds =
     {
-        switch (mi)
-        {
-            case MAP_ALBEDO: return new[] { "_BaseMap", "_MainTex" };
-            // One mask map drives three URP slots: _MetallicGlossMap (R/A) + _OcclusionMap (G) +
-            // _ParallaxMap (G = occlusion reused as a 0.5-centred height for parallax/relief).
-            case MAP_MSO: return new[] { "_MetallicGlossMap", "_OcclusionMap", "_ParallaxMap" };
-            default: return new[] { "_EmissionMap" };
-        }
-    }
+        new[] { BaseMapId, MainTexId },                              // MAP_ALBEDO
+        new[] { MetallicGlossMapId, OcclusionMapId, ParallaxMapId }, // MAP_MSO
+        new[] { EmissionMapId },                                     // MAP_EM
+    };
 
     private void AssignMapTexture(int mi, Texture tex)
     {
         if (!_materialInstance) return;
-        foreach (var p in MapProps(mi))
-        {
-            int id = Shader.PropertyToID(p);
+        foreach (int id in MapPropIds[mi])
             if (_materialInstance.HasProperty(id)) _materialInstance.SetTexture(id, tex);
-        }
     }
 }