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/OnlineSessionManager.cs

@@ -149,14 +149,30 @@ public class OnlineSessionManager : MonoBehaviour
         }
     }
 
-    private async void HostAsync()
+    // Shared busy/sign-in/error skeleton around one session operation; the body carries the
+    // op-specific statuses and state.
+    private async System.Threading.Tasks.Task RunSessionOpAsync(string failLabel, Func<System.Threading.Tasks.Task> body)
     {
-        if (_busy || IsConnected) return;
         SetBusy(true);
         try
         {
             SetStatus("Signing in…");
             await EnsureSignedInAsync();
+            await body();
+        }
+        catch (Exception e)
+        {
+            SetStatus($"{failLabel} failed: {e.Message}");
+            Debug.LogException(e);
+        }
+        finally { SetBusy(false); }
+    }
+
+    private async void HostAsync()
+    {
+        if (_busy || IsConnected) return;
+        await RunSessionOpAsync("Host", async () =>
+        {
             SetStatus("Creating session…");
             var options = new SessionOptions
             {
@@ -165,55 +181,31 @@ public class OnlineSessionManager : MonoBehaviour
             }.WithRelayNetwork();
             _session = await MultiplayerService.Instance.CreateSessionAsync(options);
             SetStatus($"Hosting \"{_session.Name}\" (code {_session.Code})");
-        }
-        catch (Exception e)
-        {
-            SetStatus($"Host failed: {e.Message}");
-            Debug.LogException(e);
-        }
-        finally { SetBusy(false); }
+        });
     }
 
     private async void RefreshAsync()
     {
         if (_busy) return;
-        SetBusy(true);
-        try
+        await RunSessionOpAsync("Refresh", async () =>
         {
-            SetStatus("Signing in…");
-            await EnsureSignedInAsync();
             SetStatus("Querying sessions…");
             var results = await MultiplayerService.Instance.QuerySessionsAsync(new QuerySessionsOptions());
             _sessions = new List<ISessionInfo>(results.Sessions);
             SessionsChanged?.Invoke();
             SetStatus($"{_sessions.Count} session(s) found");
-        }
-        catch (Exception e)
-        {
-            SetStatus($"Refresh failed: {e.Message}");
-            Debug.LogException(e);
-        }
-        finally { SetBusy(false); }
+        });
     }
 
     private async void JoinAsync(string sessionId)
     {
         if (_busy || IsConnected || string.IsNullOrEmpty(sessionId)) return;
-        SetBusy(true);
-        try
+        await RunSessionOpAsync("Join", async () =>
         {
-            SetStatus("Signing in…");
-            await EnsureSignedInAsync();
             SetStatus("Joining session…");
             _session = await MultiplayerService.Instance.JoinSessionByIdAsync(sessionId);
             SetStatus($"Joined \"{_session.Name}\"");
-        }
-        catch (Exception e)
-        {
-            SetStatus($"Join failed: {e.Message}");
-            Debug.LogException(e);
-        }
-        finally { SetBusy(false); }
+        });
     }
 
     private async void DisconnectAsync()