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/MatchManager.cs

@@ -139,7 +139,6 @@ public class MatchManager : MonoBehaviour
     // The countdown is cosmetic/local; the authoritative transition is server-driven, so drift self-corrects.
     private MatchSubPhase _subPhase = MatchSubPhase.None;
     private float _phaseEndTime;     // Time.time when the current sub-phase ends (for the HUD countdown)
-    private float _phaseDuration;
     private MatchMode _localMode = MatchMode.Classic; // mirror of the server's matchMode, carried in the phase message
 
     private const string PreMatchTag = "PreMatch"; // scene props destroyed when seek starts
@@ -152,10 +151,6 @@ public class MatchManager : MonoBehaviour
     public MatchMode LocalMatchMode => _localMode;
     /// <summary>Seconds left in the current sub-phase for the HUD (clamped to 0; cosmetic).</summary>
     public float LocalPhaseRemaining => Mathf.Max(0f, _phaseEndTime - Time.time);
-    /// <summary>Total length of the current sub-phase (for a HUD progress bar, if wanted).</summary>
-    public float LocalPhaseDuration => _phaseDuration;
-    /// <summary>Raised after the local sub-phase changes (argument = the new sub-phase). HUD/visibility follow it.</summary>
-    public event System.Action<MatchSubPhase> SubPhaseChanged;
 
     private NetworkManager _net;
     private GameObject _playerPrefab; // captured from NetworkConfig.PlayerPrefab; auto-spawn is then disabled so we spawn manually into a loaded scene
@@ -508,21 +503,16 @@ public class MatchManager : MonoBehaviour
         BroadcastPhase(phase, duration, matchMode, 0, true);
     }
 
-    // Sets this machine's sub-phase mirror + countdown + mode and notifies followers (HUD / visibility).
+    // Sets this machine's sub-phase mirror + countdown + mode (followers poll LocalSubPhase).
     // Shared by the server's SetPhaseServer and a client's OnPhaseMessage handler.
     private void ApplyPhaseLocal(MatchSubPhase phase, float duration, MatchMode mode)
     {
         bool changed = _subPhase != phase;
         _subPhase = phase;
-        _phaseDuration = duration;
         _phaseEndTime = Time.time + duration;
         _localMode = mode;
-        if (changed)
-        {
-            SubPhaseChanged?.Invoke(phase);
-            // Props staged only for the hide phase are gone the instant seek begins.
-            if (phase == MatchSubPhase.Seek) DestroyPreMatchObjects();
-        }
+        // Props staged only for the hide phase are gone the instant seek begins.
+        if (changed && phase == MatchSubPhase.Seek) DestroyPreMatchObjects();
     }
 
     // Runs on every machine (server directly, clients via the phase message); the tagged props are plain
@@ -801,7 +791,7 @@ public class MatchManager : MonoBehaviour
 
     /// <summary>Ends the running match for everyone (back to the Lobby), routed through authority: the
     /// host/server ends directly; a remote authority client asks the server. No-op if this machine is not
-    /// the authority or no match is running. Replaces the old Esc handler - now driven by the panel button.</summary>
+    /// the authority or no match is running.</summary>
     public void RequestEndMatch()
     {
         if (_net == null) return;
@@ -811,9 +801,26 @@ public class MatchManager : MonoBehaviour
 
     // Local active-scene kind. Every peer sets its active scene to Lobby/Map as those load (see OnSceneEvent)
     // and back to Main on teardown, so a local UI can tell where it is without the server-local Phase.
-    public bool IsLocalSceneMain  => SceneManager.GetActiveScene().name == mainSceneName;
-    public bool IsLocalSceneLobby => SceneManager.GetActiveScene().name == lobbySceneName;
-    public bool IsLocalSceneMap   => SceneManager.GetActiveScene().name == matchSceneName;
+    // Scene.name allocates a fresh string per call and these are polled per frame -> cached per scene handle.
+    public bool IsLocalSceneLobby => ActiveSceneName == lobbySceneName;
+    public bool IsLocalSceneMap   => ActiveSceneName == matchSceneName;
+
+    private int _activeSceneHandle;
+    private string _activeSceneName;
+
+    private string ActiveSceneName
+    {
+        get
+        {
+            Scene s = SceneManager.GetActiveScene();
+            if (_activeSceneName == null || s.handle != _activeSceneHandle)
+            {
+                _activeSceneHandle = s.handle;
+                _activeSceneName = s.name;
+            }
+            return _activeSceneName;
+        }
+    }
 
     // Sends a named message whose payload carries no information (a named message still needs a buffer,
     // so a single dummy byte is written).