🔧(frontend) make web app manifest optional

Add configuration to conditionally include manifest article,
allowing deployments to customize or disable MoreLink component.

src/frontend/src/api/useConfig.ts

@@ -30,6 +30,7 @@ export interface ApiConfig {
     available_modes?: RecordingMode[]
     expiration_days?: number
   }
+  manifest_link?: string
 }
 
 const fetchConfig = (): Promise<ApiConfig> => {

src/frontend/src/features/home/components/MoreLink.tsx

@@ -2,17 +2,16 @@ import { A, Text } from '@/primitives'
 import { useTranslation } from 'react-i18next'
 import { useConfig } from '@/api/useConfig'
 
-const MANIFEST_LINK =
-  'https://docs.numerique.gouv.fr/docs/1ef86abf-f7e0-46ce-b6c7-8be8b8af4c3d/'
-
 export const MoreLink = () => {
   const { t } = useTranslation('home')
   const { data } = useConfig()
 
+  if (!data?.manifest_link) return
+
   return (
     <Text as={'p'} variant={'sm'} style={{ padding: '1rem 0' }}>
       <A
-        href={MANIFEST_LINK}
+        href={data?.manifest_link}
         target="_blank"
         rel="noopener noreferrer"
         aria-label={t('moreLinkLabel')}