a11y: corrections accessibilité WCAG 2.1 (critères 4.1.2, 4.1.3, 1.3.1)

sign.js :
- aria-label sur les 4 Fab (Se déconnecter, dashboard, Se connecter, S'enregistrer)
- Correction des guillemets typographiques U+2018/U+2019 en ASCII (empêchaient le parsing JSX)
- Suppression de useMemo inutilisé
- IIFE async ;() → startSubscription() nommée + .catch() explicite (semi-style + no-void)

auth-form/index.js :
- aria-label des IconButton visibility traduits en français avec état dynamique :
  'Afficher/Masquer le mot de passe' et 'Afficher/Masquer la vérification'

version-timeline.js :
- aria-label='Comparer les versions' sur IconButton Comparer
- aria-label dynamique + aria-expanded sur le bouton expand/collapse
- Correction object-curly-newline et jsx-closing-bracket-location (pré-existants)

version-search.js :
- inputProps aria-label='Rechercher dans les versions' (placeholder seul insuffisant)

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

components/session/sign.js

@@ -1,7 +1,7 @@
 'use client'
 
 import PropTypes from 'prop-types'
-import {useEffect, useState, useMemo} from 'react'
+import {useEffect, useState} from 'react'
 import {signOut} from 'next-auth/react'
 import {useRouter} from 'next/navigation'
 import Box from '@mui/material/Box'
@@ -70,7 +70,7 @@ export default function Sign({session, navButton}) {
               console.log('WebSocket authenticated successfully!')
 
               // Subscribe to version changes
-              ;(async () => {
+              const startSubscription = async () => {
                 const {subscription} = await client.subscribe('directus_versions', {
                   event: 'create',
                   query: {
@@ -86,7 +86,9 @@ export default function Sign({session, navButton}) {
                 for await (const item of subscription) {
                   console.log('New version created:', item)
                 }
-              })()
+              }
+
+              startSubscription().catch(error => console.error('Subscription error:', error))
             }
           })
 
@@ -117,12 +119,12 @@ export default function Sign({session, navButton}) {
         {session ? (
           <Stack direction='row' spacing={2}>
             <LightTooltip title='Se déconnecter' placement='right'>
-              <Fab size='large' color='error' onClick={() => setIsOpen(true)}>
+              <Fab size='large' color='error' aria-label='Se déconnecter' onClick={() => setIsOpen(true)}>
                 <LogoutIcon fontSize='large' />
               </Fab>
             </LightTooltip>
             <LightTooltip title={navButton.title} placement='right'>
-              <Fab sx={{mr: 3}} size='large' color={navButton.color} onClick={() => router.push(navButton.path)}>
+              <Fab sx={{mr: 3}} size='large' color={navButton.color} aria-label={navButton.title} onClick={() => router.push(navButton.path)}>
                 {navButton.icon}
               </Fab>
             </LightTooltip>
@@ -130,12 +132,12 @@ export default function Sign({session, navButton}) {
         ) : (
           <Stack direction='row' spacing={2}>
             <LightTooltip title='Se connecter' placement='left'>
-              <Fab size='large' color='success' onClick={() => router.push('/login')}>
+              <Fab size='large' color='success' aria-label='Se connecter' onClick={() => router.push('/login')}>
                 <LoginIcon fontSize='large' />
               </Fab>
             </LightTooltip>
-            <LightTooltip title='S’enregistrer' placement='right'>
-              <Fab size='large' color='success' onClick={() => router.push('/register')}>
+            <LightTooltip title="S'enregistrer" placement='right'>
+              <Fab size='large' color='success' aria-label="S'enregistrer" onClick={() => router.push('/register')}>
                 <PersonAddIcon fontSize='large' />
               </Fab>
             </LightTooltip>