refactor: item 29 cleanup

F16 F17 F18 F19 F20 F21: import polling backs off and pauses in a hidden tab, one date format module, fake timers in the import tests, error codes instead of raw messages, one safe storage wrapper, dead code.

src/components/GameCorrectionDialog.jsx

@@ -12,6 +12,8 @@ import {CORRECTABLE_MOODS, IGDB_GENRES, resetCorrection, saveCorrection} from '.
 import {genreKey} from '../utils/stats.js';
 import {MAX_CORRECTION_GENRES, MAX_CORRECTION_LENGTH} from '../utils/limits.js';
 
+const REFUSAL_KEY = {INVALID_CORRECTION: 'CORRECTION.INVALID'};
+
 const ENDLESS_CHOICES = [[null, 'UNKNOWN'], [true, 'YES'], [false, 'NO']];
 
 const initialValues = (game) => ({
@@ -68,8 +70,9 @@ export default function GameCorrectionDialog({game, open, onOpenChange, onChange
                 return;
             }
             const data = await response.json().catch(() => ({}));
-            toast.error(data.code === 'INVALID_CORRECTION' ? t('CORRECTION.INVALID', {message: data.message})
-                : response.status === 403 ? t('CORRECTION.NO_ACCESS') : t('CORRECTION.ERROR'));
+            // Core's message is English and for developers, so it goes to the console only.
+            if (data.message) console.warn('Correction refused:', data.code, data.message);
+            toast.error(t(REFUSAL_KEY[data.code] ?? (response.status === 403 ? 'CORRECTION.NO_ACCESS' : 'CORRECTION.ERROR')));
         } catch (err) {
             console.error('Correction error:', err);
             toast.error(t('INFO.ERROR.NETWORK_FAILURE'));