fix: unify theme system - fix theme switching persistence

- Unified localStorage key to 'theme-preference' across all components
- Fixed header.tsx using wrong localStorage key ('theme' instead of 'theme-preference')
- Added localStorage hybrid persistence for instant theme changes
- Removed router.refresh() which was causing stale data revert
- Replaced Blue theme with Sepia
- Consolidated auth() calls to prevent race conditions
- Updated UserSettingsData types to include all themes

keep-notes/app/(main)/settings/profile/profile-form.tsx

@@ -125,7 +125,7 @@ export function ProfileForm({ user, userAISettings }: { user: any; userAISetting
   const handleShowRecentNotesChange = async (enabled: boolean) => {
     setIsUpdatingRecentNotes(true)
     const previousValue = showRecentNotes
-    
+
     try {
       const result = await updateShowRecentNotes(enabled)
       if (result?.error) {
@@ -209,56 +209,7 @@ export function ProfileForm({ user, userAISettings }: { user: any; userAISetting
         </CardContent>
       </Card>
 
-      <Card>
-        <CardHeader>
-          <CardTitle>{t('profile.displaySettings')}</CardTitle>
-          <CardDescription>{t('profile.displaySettingsDescription')}</CardDescription>
-        </CardHeader>
-        <CardContent className="space-y-4">
-          <div className="space-y-2">
-            <Label htmlFor="fontSize">{t('profile.fontSize')}</Label>
-            <Select
-              value={fontSize}
-              onValueChange={handleFontSizeChange}
-              disabled={isUpdatingFontSize}
-            >
-              <SelectTrigger id="fontSize">
-                <SelectValue placeholder={t('profile.selectFontSize')} />
-              </SelectTrigger>
-              <SelectContent>
-                {FONT_SIZES.map((size) => (
-                  <SelectItem key={size.value} value={size.value}>
-                    <span className="flex items-center gap-2">
-                      <span>{size.label}</span>
-                      <span className="text-xs text-muted-foreground">({size.size})</span>
-                    </span>
-                  </SelectItem>
-                ))}
-              </SelectContent>
-            </Select>
-            <p className="text-sm text-muted-foreground">
-              {t('profile.fontSizeDescription')}
-            </p>
-          </div>
-          
-          <div className="flex items-center justify-between pt-4 border-t">
-            <div className="space-y-0.5">
-              <Label htmlFor="showRecentNotes" className="text-base font-medium">
-                {t('profile.showRecentNotes') || 'Afficher la section Récent'}
-              </Label>
-              <p className="text-sm text-muted-foreground">
-                {t('profile.showRecentNotesDescription') || 'Afficher les notes récentes (7 derniers jours) sur la page principale'}
-              </p>
-            </div>
-            <Switch
-              id="showRecentNotes"
-              checked={showRecentNotes}
-              onCheckedChange={handleShowRecentNotesChange}
-              disabled={isUpdatingRecentNotes}
-            />
-          </div>
-        </CardContent>
-      </Card>
+
 
       <Card>
         <CardHeader>