Refactor: extract shared helpers across scripts, trim remaining doc redundancy

Deduplication pass (44 extractions):
- New SmoothedLook: shared smoothed yaw/pitch look tick + view seeding
  (FirstPersonController, FreeCamController)
- New CharacterTeleport: disable-CC-around-teleport idiom (rescue,
  owner position apply, free-cam sync)
- New GeometryUtil: RescaleToUnitScale + TransformBounds (concealment
  meter/volume, skinned collider baker)
- Paint family: canonical map read/write shared between Net and
  Persistence, snapshot decode, backend stroke dispatch, RebuildBackend,
  ResolveSeed, chunked RPC send/gate/copy, CamoKnobs/HeightKnobs
  aggregates, SanitizeFileKey, NewMaskTexture, AdoptAlbedo, FindSlider
- Player/modes: GameMode SetPlayerControl/SetPainting/SetOrbitInputEnabled,
  InputUtil.GameplayKeyPressed, NearestClimbHit, ComputeXRay delegates to
  ComputeResolutionFreeze, FingerIK TryInPlaneAngle
- Match/misc: UnhookSessionCallbacks, SendEmptyNamedMessage, SwapScenes,
  RunSessionOpAsync, CovarianceEigen, CollectClusterPoints, MatchHud
  GUIStyle cache, HsvColorPicker rehook, VoxelCenter

Documentation pass: remove 6 triplicated doc blocks and 2 restating
inline comments left after the previous reduction.

Behavior-neutral; hot-path rasterizer loops intentionally untouched.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/Scripts/GameModeManager.cs

@@ -145,14 +145,25 @@ public class GameModeManager : MonoBehaviour
         _paused = false;
         _resumeIndex = -1;
 
+        ClearPlayerBindings();
+        TearDownActiveMode();
+        BuildSpectatorModes();
+        SwitchTo(0);
+    }
+
+    /// <summary>Drops the player/painter bindings and notifies painter-following UI.</summary>
+    private void ClearPlayerBindings()
+    {
         player = null;
         painter = null;
         PainterChanged?.Invoke(null);
+    }
 
+    /// <summary>Exits the active mode and marks no mode active.</summary>
+    private void TearDownActiveMode()
+    {
         ActiveMode?.Exit();
         _activeIndex = -1;
-        BuildSpectatorModes();
-        SwitchTo(0);
     }
 
     /// <summary>
@@ -197,8 +208,7 @@ public class GameModeManager : MonoBehaviour
             firstPerson.SetPlayer(localPlayer);
 
         // Tear down the pre-spawn (player-less) mode and rebuild scoped to this avatar's role.
-        ActiveMode?.Exit();
-        _activeIndex = -1;
+        TearDownActiveMode();
 
         // Lobby avatar -> full set; match variant -> its role's modes. Scope is baked per prefab
         // variant, so it follows the spawned avatar with no replicated-phase timing race.
@@ -224,12 +234,9 @@ public class GameModeManager : MonoBehaviour
         _paused = false;
         _resumeIndex = -1;
 
-        ActiveMode?.Exit();
-        _activeIndex = -1;
+        TearDownActiveMode();
         _modes.Clear();
-        player = null;
-        painter = null;
-        PainterChanged?.Invoke(null);
+        ClearPlayerBindings();
 
         // The cycle is empty (no SwitchTo runs), so notify mode-following UI explicitly - otherwise the
         // paint HUD (hides only via ModeChanged) would stay open after a shutdown during PaintMode.
@@ -308,7 +315,7 @@ public class GameModeManager : MonoBehaviour
             else if (painter) painter.PaintingEnabled = false; // degenerate paint-only set: at least stop painting
         }
 
-        if (WasSwitchPressed())
+        if (InputUtil.GameplayKeyPressed(switchKey))
         {
             int next = (_activeIndex + 1) % _modes.Count;
             if (suppressPaint && _modes[next] is PaintMode)
@@ -355,14 +362,4 @@ public class GameModeManager : MonoBehaviour
         Debug.Log($"[GameModeManager] Mode -> {ActiveMode.DisplayName}", this);
         ModeChanged?.Invoke(ActiveMode);
     }
-
-    private bool WasSwitchPressed()
-    {
-        if (TypingGuard.IsTyping) return false;
-#if ENABLE_INPUT_SYSTEM
-        return Keyboard.current != null && Keyboard.current[switchKey].wasPressedThisFrame;
-#else
-        return Input.GetKeyDown(switchKey);
-#endif
-    }
 }