fix: i18n complet — mobile, backlinks, undo/redo, content-area

- mobile-action-sheet.tsx: 15 chaînes → t()
- wikilinks-backlinks-panel.tsx: 3 chaînes → t() + import useLanguage
- note-content-area.tsx: 'Cliquez pour éditer' → t()
- undo-redo-feedback-extension.ts: strings → options configurables
- i18n FR/EN: 11 nouvelles clés (mobile.*, editor.*)
- SlashPreview et SlashCommand: déjà OK (i18n via localCommands)

memento-note/components/mobile-action-sheet.tsx

@@ -101,84 +101,84 @@ export function MobileActionSheet({
         <div className="mobile-action-sheet-body">
           {/* Section 1 : Actions de bloc */}
           <div className="mobile-action-sheet-section">
-            <h4 className="section-title">Actions sur le bloc</h4>
+            <h4 className="section-title">{t('mobile.blockActions') || 'Actions sur le bloc'}</h4>
             <div className="grid grid-cols-3 gap-2">
               <button type="button" className="action-tile-btn" onClick={handleSelectAllBlock}>
                 <FileText size={20} className="text-blue-500" />
-                <span>Sélectionner tout</span>
+                <span>{t('mobile.selectAll') || 'Sélectionner tout'}</span>
               </button>
               <button type="button" className="action-tile-btn" onClick={handleDuplicateBlock}>
                 <Copy size={20} className="text-emerald-500" />
-                <span>Dupliquer</span>
+                <span>{t('mobile.duplicate') || 'Dupliquer'}</span>
               </button>
               <button type="button" className="action-tile-btn text-rose-500" onClick={handleDeleteBlock}>
                 <Trash2 size={20} className="text-rose-500" />
-                <span>Supprimer</span>
+                <span>{t('mobile.delete') || 'Supprimer'}</span>
               </button>
             </div>
           </div>
 
           {/* Section 2 : IA Note */}
           <div className="mobile-action-sheet-section">
-            <h4 className="section-title">IA Note</h4>
+            <h4 className="section-title">{t('mobile.aiNote') || 'IA Note'}</h4>
             <div className="grid grid-cols-4 gap-2">
               <button type="button" className="action-tile-btn" onClick={() => handleAiAction('improve')}>
                 <Wand2 size={18} className="text-purple-500 animate-pulse" />
-                <span className="text-[10px]">Améliorer</span>
+                <span className="text-[10px]">{t('richTextEditor.slashImprove') || 'Améliorer'}</span>
               </button>
               <button type="button" className="action-tile-btn" onClick={() => handleAiAction('clarify')}>
                 <Lightbulb size={18} className="text-amber-500" />
-                <span className="text-[10px]">Clarifier</span>
+                <span className="text-[10px]">{t('richTextEditor.slashClarify') || 'Clarifier'}</span>
               </button>
               <button type="button" className="action-tile-btn" onClick={() => handleAiAction('shorten')}>
                 <Scissors size={18} className="text-indigo-500" />
-                <span className="text-[10px]">Raccourcir</span>
+                <span className="text-[10px]">{t('richTextEditor.slashShorten') || 'Raccourcir'}</span>
               </button>
               <button type="button" className="action-tile-btn" onClick={() => handleAiAction('expand')}>
                 <Expand size={18} className="text-teal-500" />
-                <span className="text-[10px]">Développer</span>
+                <span className="text-[10px]">{t('richTextEditor.slashExpand') || 'Développer'}</span>
               </button>
             </div>
           </div>
 
           {/* Section 3 : Format de bloc */}
           <div className="mobile-action-sheet-section">
-            <h4 className="section-title">Convertir le format</h4>
+            <h4 className="section-title">{t('mobile.convertFormat') || 'Convertir le format'}</h4>
             <div className="flex gap-2 overflow-x-auto pb-2 scrollbar-none">
               <button
                 type="button"
                 className="format-pill-btn"
                 onClick={() => { editor.chain().focus().setParagraph().run(); onClose() }}
               >
-                Paragraphe
+                {t('mobile.paragraph') || 'Paragraphe'}
               </button>
               <button
                 type="button"
                 className="format-pill-btn"
                 onClick={() => { editor.chain().focus().toggleHeading({ level: 1 }).run(); onClose() }}
               >
-                <Heading1 size={14} className="inline mr-1" /> Titre 1
+                <Heading1 size={14} className="inline mr-1" /> {t('notes.heading1') || 'Titre 1'}
               </button>
               <button
                 type="button"
                 className="format-pill-btn"
                 onClick={() => { editor.chain().focus().toggleHeading({ level: 2 }).run(); onClose() }}
               >
-                <Heading2 size={14} className="inline mr-1" /> Titre 2
+                <Heading2 size={14} className="inline mr-1" /> {t('notes.heading2') || 'Titre 2'}
               </button>
               <button
                 type="button"
                 className="format-pill-btn"
                 onClick={() => { editor.chain().focus().toggleHeading({ level: 3 }).run(); onClose() }}
               >
-                <Heading3 size={14} className="inline mr-1" /> Titre 3
+                <Heading3 size={14} className="inline mr-1" /> {t('notes.heading3') || 'Titre 3'}
               </button>
               <button
                 type="button"
                 className="format-pill-btn"
                 onClick={() => { editor.chain().focus().toggleBlockquote().run(); onClose() }}
               >
-                <Quote size={14} className="inline mr-1" /> Citation
+                <Quote size={14} className="inline mr-1" /> {t('mobile.quote') || 'Citation'}
               </button>
             </div>
           </div>

memento-note/components/note-editor/note-content-area.tsx

@@ -40,7 +40,7 @@ export function NoteContentArea() {
         <MarkdownContent content={state.content} />
         {!readOnly && (
           <p className="text-[11px] text-foreground/30 mt-8 select-none not-prose italic">
-            Cliquez pour éditer
+            {t('editor.clickToEdit') || 'Cliquez pour éditer'}
           </p>
         )}
       </div>

memento-note/components/wikilinks-backlinks-panel.tsx

@@ -5,6 +5,7 @@ import { Link2, ChevronRight, Loader2 } from 'lucide-react'
 import { cn } from '@/lib/utils'
 import { motion, AnimatePresence } from 'motion/react'
 import { useRouter } from 'next/navigation'
+import { useLanguage } from '@/lib/i18n'
 
 interface BacklinkNote {
   id: string
@@ -26,6 +27,7 @@ interface WikilinksBacklinksPanelProps {
 }
 
 export function WikilinksBacklinksPanel({ noteId, className }: WikilinksBacklinksPanelProps) {
+  const { t } = useLanguage()
   const [backlinks, setBacklinks] = useState<Backlink[]>([])
   const [loading, setLoading] = useState(true)
   const [open, setOpen] = useState(true)
@@ -54,7 +56,7 @@ export function WikilinksBacklinksPanel({ noteId, className }: WikilinksBacklink
       >
         <Link2 size={14} className="text-concrete shrink-0" />
         <span className="text-[10px] uppercase tracking-[0.25em] font-bold text-concrete group-hover:text-ink transition-colors">
-          Liens entrants
+          {t('editor.backlinks') || 'Liens entrants'}
         </span>
         <span className="text-[9px] bg-brand-accent/10 text-brand-accent px-1.5 py-0.5 rounded-full font-bold">
           {backlinks.length}
@@ -78,7 +80,7 @@ export function WikilinksBacklinksPanel({ noteId, className }: WikilinksBacklink
             {loading && (
               <div className="flex items-center gap-2 py-2">
                 <Loader2 size={12} className="animate-spin text-concrete" />
-                <span className="text-[10px] text-concrete">Chargement…</span>
+                <span className="text-[10px] text-concrete">{t('common.loading') || 'Chargement…'}</span>
               </div>
             )}
             {backlinks.map(bl => (
@@ -92,7 +94,7 @@ export function WikilinksBacklinksPanel({ noteId, className }: WikilinksBacklink
                   <Link2 size={10} className="text-brand-accent/60 mt-0.5 shrink-0" />
                   <div className="min-w-0 flex-1">
                     <p className="text-[11px] font-semibold text-ink truncate group-hover/bl:text-brand-accent transition-colors">
-                      {bl.sourceNote.title || '(Sans titre)'}
+                      {bl.sourceNote.title || (t('notes.untitled') || '(Sans titre)')}
                     </p>
                     {bl.contextSnippet && (
                       <p className="text-[9px] text-concrete/70 mt-0.5 line-clamp-2 leading-relaxed">