fix(settings): remove the duplicated section heading on 11 tabs

A generic shell heading stacked on top of each tab component's own internal
heading. The report named five tabs "at least"; auditing all 28 found 11:
downloads, sso, apiTokens, webhooks, businessProfile, crm, accounting,
whatsapp, slideshow, moderation, styling. On the first eight the two headings
resolve to the identical string -- sso and businessProfile literally render
the same key twice. The other three were near-identical stacked titles
("Moderation"/"Word Filters", "Custom CSS"/"Custom CSS Templates",
"CRM behaviour"/"CRM settings").

Clean, and left alone: general, events, categories, thumbnails, security, seo,
imageSecurity, status, analytics (its first heading is a genuine sub-section),
plus the eight already in TABS_WITH_OWN_HEADER.

Removed the component side and kept the shell heading: the shell heading is
the consistent one (icon + label + divider on ~20 tabs) and always matches the
nav item the admin clicked, and none of these components are mounted outside
SettingsPage, so nothing loses a title. Subtitles and intro copy preserved
throughout; orphaned icon imports removed.

The guard test was checked against the pre-fix blobs and does fail on them.

Refs testplan REPORT.md, "duplicate H2 section heading" warning.

frontend/src/components/admin/CssTemplateEditor.tsx

@@ -2,7 +2,7 @@ import React, { useState, useEffect } from 'react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useTranslation } from 'react-i18next';
 import { toast } from 'react-toastify';
-import { Save, RotateCcw, Code, AlertTriangle, Check } from 'lucide-react';
+import { Save, RotateCcw, AlertTriangle, Check } from 'lucide-react';
 import { Button, Card, Loading } from '../common';
 import { cssTemplatesService, CssTemplate } from '../../services/cssTemplates.service';
 import { useLocalizedDate } from '../../hooks/useLocalizedDate';
@@ -90,12 +90,10 @@ export const CssTemplateEditor: React.FC = () => {
   return (
     <Card>
       <div className="p-6">
-        <div className="flex items-center justify-between mb-6">
-          <h2 className="text-lg font-semibold text-neutral-900 dark:text-neutral-100 flex items-center gap-2">
-            <Code className="w-5 h-5" />
-            {t('cssTemplates.title', 'Custom CSS Templates')}
-          </h2>
-        </div>
+        {/* No title here — this component IS the Settings → Custom CSS
+            tab, and the Settings shell already renders that section
+            heading (icon + label + divider). A second, near-identical H2
+            stacked directly under it (QA warning). */}
 
         {/* Tab Navigation */}
         <div className="flex border-b border-neutral-200 dark:border-neutral-700 mb-6">

frontend/src/components/admin/WordFilterManager.tsx

@@ -176,10 +176,11 @@ export const WordFilterManager: React.FC = () => {
     <>
       <Card>
         <div className="p-6">
+          {/* No title here — this component IS the Settings → Moderation
+              tab, and the Settings shell already renders that section
+              heading (icon + label + divider). A second H2 stacked
+              directly under it (QA warning). */}
           <div className="mb-6">
-            <h2 className="text-lg font-semibold text-neutral-900 dark:text-neutral-100 mb-2">
-              {t('settings.moderation.wordFilters', 'Word Filters')}
-            </h2>
             <p className="text-sm text-neutral-600 dark:text-neutral-400">
               {t('settings.moderation.description', 'Manage words that should be filtered or blocked in comments')}
             </p>