Phase A: clear all react-hooks/exhaustive-deps warnings via useEffectEvent or hoisting

Eliminate the four remaining missing-dependency warnings reported by
react-hooks v7. Each one was a real stale-closure or re-trigger hazard;
the fix matches the intent rather than just silencing the linter.

- src/App.tsx (line 448): wrap showSessionExpired with useEffectEvent
  (onSessionExpired) so the prepare effect doesn't re-run on every
  showSessionExpired identity change but still calls the latest
  callback. Replace the two in-effect call sites.
- src/components/furni-editor/views/FurniEditorSearchView.tsx: wrap
  the on-mount onSearch('', '', 1) call with useEffectEvent so the
  callback prop isn't a missing dependency.
- src/components/notification-center/views/bubble-layouts/
  NotificationBadgeReceivedBubbleView.tsx: wrap the
  "fetch badges only if empty on mount" check with useEffectEvent
  so badgeCodes.length isn't required as a dep (and won't re-fetch
  every count change).
- src/components/navigator/views/room-settings/
  NavigatorRoomSettingsRightsTabView.tsx: switch deps from
  roomData?.roomId to roomData (the body uses roomData.roomId after
  an early return; the linter wanted the whole object).
- src/api/ui-settings/UiSettingsContext.tsx: hoist ALL_CSS_VARS
  outside the component (it's a static constant).

After this, yarn eslint reports zero exhaustive-deps warnings across
the whole src/.

https://claude.ai/code/session_01GrR87LAqnAEyKG2ZbmQt5Q

src/App.tsx

@@ -1,5 +1,5 @@
 import { GetAssetManager, GetAvatarRenderManager, GetCommunication, GetConfiguration, GetLocalizationManager, GetRoomEngine, GetRoomSessionManager, GetSessionDataManager, GetSoundManager, GetStage, GetTexturePool, GetTicker, HabboWebTools, LegacyExternalInterface, LoadGameUrlEvent, NitroEventType, NitroLogger, NitroVersion, PrepareRenderer } from '@nitrots/nitro-renderer';
-import { FC, useCallback, useEffect, useRef, useState } from 'react';
+import { FC, useCallback, useEffect, useEffectEvent, useRef, useState } from 'react';
 import { ClearRememberLogin, GetRememberLogin, GetUIVersion, StoreRememberLoginFromPayload } from './api';
 import { Base } from './common';
 import { LoadingView } from './components/loading/LoadingView';
@@ -316,6 +316,8 @@ export const App: FC<{}> = props =>
         };
     }, []);
 
+    const onSessionExpired = useEffectEvent(() => showSessionExpired());
+
     useEffect(() =>
     {
         const prepare = async (width: number, height: number) =>
@@ -379,7 +381,7 @@ export const App: FC<{}> = props =>
                             return;
                         }
 
-                        showSessionExpired();
+                        onSessionExpired();
                         return;
                     }
                 }
@@ -432,7 +434,7 @@ export const App: FC<{}> = props =>
             {
                 NitroLogger.error(err);
                 setIsEnteringHotel(false);
-                showSessionExpired();
+                onSessionExpired();
             }
         };