fix: remove duplicate page titles, add OG meta for review links

- Removed h1 titles from Settings and Brands (already in Header)
- Server injects og:title, og:description, og:image meta tags for
  /review-post/:token URLs so WhatsApp/Slack show proper previews

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/src/pages/Brands.jsx

@@ -129,13 +129,7 @@ export default function Brands() {
     <div className="space-y-6 animate-fade-in">
       {/* Header */}
       <div className="flex items-center justify-between">
-        <div>
-          <h1 className="text-2xl font-bold text-text-primary flex items-center gap-3">
-            <Tag className="w-7 h-7 text-brand-primary" />
-            {t('brands.title')}
-          </h1>
-          <p className="text-sm text-text-tertiary mt-1">{t('brands.manageBrands')}</p>
-        </div>
+        <p className="text-sm text-text-tertiary">{t('brands.manageBrands')}</p>
         {isSuperadminOrManager && (
           <button
             onClick={openNewBrand}

client/src/pages/Settings.jsx

@@ -62,14 +62,7 @@ export default function Settings() {
 
   return (
     <div className="space-y-6 animate-fade-in max-w-3xl">
-      {/* Header */}
-      <div>
-        <h1 className="text-2xl font-bold text-text-primary flex items-center gap-3">
-          <SettingsIcon className="w-7 h-7 text-brand-primary" />
-          {t('settings.title')}
-        </h1>
-        <p className="text-sm text-text-tertiary mt-1">{t('settings.preferences')}</p>
-      </div>
+      <p className="text-sm text-text-tertiary">{t('settings.preferences')}</p>
 
       {/* General Settings */}
       <div className="bg-white rounded-xl border border-border overflow-hidden">