fix(web): render custom HTML and Markdown content consistently (#5760)

* fix(markdown): render announcement markdown consistently

- support soft line breaks for announcement markdown without changing the default parser behavior.
- add explicit markdown element styles so lists, tables, code blocks, and quotes render correctly when typography styles are unavailable.
- apply the announcement markdown mode in both the popover and detail dialog for consistent display.

* refactor(markdown): simplify fallback markdown styles

- remove duplicate typography utility classes now covered by explicit markdown element fallbacks.
- keep the markdown renderer behavior unchanged while reducing class noise.
- modernize small helper expressions to satisfy targeted lint checks.

* fix(content): render custom HTML consistently

- add shared rich content rendering so custom HTML and Markdown use the same path across public pages and announcements.
- reuse common URL and HTML detection instead of duplicating content format checks per page.
- keep custom home content inside the standard public layout while preserving full-page iframe rendering for external URLs.

web/default/src/features/about/index.tsx

@@ -19,24 +19,12 @@ For commercial licensing, please contact support@quantumnous.com
 import { useQuery } from '@tanstack/react-query'
 import { Construction } from 'lucide-react'
 import { useTranslation } from 'react-i18next'
-import { Markdown } from '@/components/ui/markdown'
+import { RichContent } from '@/components/rich-content'
 import { Skeleton } from '@/components/ui/skeleton'
 import { PublicLayout } from '@/components/layout'
+import { isHttpUrl } from '@/lib/content-format'
 import { getAboutContent } from './api'
 
-function isValidUrl(value: string) {
-  try {
-    const url = new URL(value)
-    return url.protocol === 'http:' || url.protocol === 'https:'
-  } catch {
-    return false
-  }
-}
-
-function isLikelyHtml(value: string) {
-  return /<\/?[a-z][\s\S]*>/i.test(value)
-}
-
 function EmptyAboutState() {
   const { t } = useTranslation()
   const currentYear = new Date().getFullYear()
@@ -131,8 +119,7 @@ export function About() {
 
   const rawContent = data?.data?.trim() ?? ''
   const hasContent = rawContent.length > 0
-  const isUrl = hasContent && isValidUrl(rawContent)
-  const isHtml = hasContent && !isUrl && isLikelyHtml(rawContent)
+  const isUrl = hasContent && isHttpUrl(rawContent)
 
   if (isLoading) {
     return (
@@ -162,6 +149,7 @@ export function About() {
           src={rawContent}
           className='h-[calc(100vh-3.5rem)] w-full border-0'
           title={t('About')}
+          sandbox='allow-forms allow-popups allow-popups-to-escape-sandbox allow-scripts'
         />
       </PublicLayout>
     )
@@ -170,16 +158,10 @@ export function About() {
   return (
     <PublicLayout>
       <div className='mx-auto max-w-6xl px-4 py-8'>
-        {isHtml ? (
-          <div
-            className='prose prose-neutral dark:prose-invert max-w-none'
-            dangerouslySetInnerHTML={{ __html: rawContent }}
-          />
-        ) : (
-          <Markdown className='prose-neutral dark:prose-invert max-w-none'>
-            {rawContent}
-          </Markdown>
-        )}
+        <RichContent
+          content={rawContent}
+          className='prose-neutral dark:prose-invert max-w-none'
+        />
       </div>
     </PublicLayout>
   )