fix: exercices dans panneau IA + erreur language

- Générateur d'exercices déplacé du menu ⋯ vers le panneau IA (onglet Actions > Outils de génération)
- Même design que les cartes slides/diagrammes
- Fix: import useLanguage supprimé de la route API (hook client en serveur)
- i18n FR/EN

memento-note/components/contextual-ai-chat.tsx

@@ -218,7 +218,7 @@ export function ContextualAIChat({
   const [translateTarget, setTranslateTarget] = useState('')
 
   // Generate slides / diagram state
-  const [generateLoading, setGenerateLoading] = useState<'slides' | 'diagram' | null>(null)
+  const [generateLoading, setGenerateLoading] = useState<'slides' | 'diagram' | 'exercises' | null>(null)
   const [generateProgress, setGenerateProgress] = useState(0)
   const [generateResult, setGenerateResult] = useState<GenerateResult | null>(null)
   const [customLangInput, setCustomLangInput] = useState('')
@@ -1228,6 +1228,54 @@ export function ContextualAIChat({
                   </div>
                 </div>
 
+                {/* ── Générateur d'exercices ── */}
+                {noteId && (
+                  <div className="group relative p-6 rounded-2xl bg-white border border-border hover:border-brand-accent/30 transition-all duration-500 overflow-hidden">
+                    <div className="absolute top-0 right-0 p-4 opacity-5 group-hover:opacity-10 transition-opacity">
+                      <PenTool size={80} className="text-brand-accent" />
+                    </div>
+                    <div className="relative space-y-4">
+                      <div className="flex items-center gap-3">
+                        <div className="p-2 bg-slate-50 rounded-lg text-brand-accent"><PenTool size={18} /></div>
+                        <div className="space-y-0.5">
+                          <h5 className="text-sm font-bold text-foreground leading-none">{t('ai.generate.exercises') || 'Générer des exercices'}</h5>
+                          <p className="text-[9px] text-foreground/40 uppercase tracking-tight">{t('ai.generate.exercisesHint') || '5 exercices avec corrigés'}</p>
+                        </div>
+                      </div>
+                      <p className="text-[10px] text-foreground/50 leading-relaxed">
+                        {t('ai.generate.exercisesDesc') || "L'IA crée 5 exercices basés sur cette note, avec des niveaux de difficulté variés et des corrigés détaillés."}
+                      </p>
+                      <button
+                        onClick={async () => {
+                          if (!noteId) return
+                          setGenerateLoading('exercises')
+                          try {
+                            const res = await fetch('/api/ai/generate-exercises', {
+                              method: 'POST',
+                              headers: { 'Content-Type': 'application/json' },
+                              body: JSON.stringify({ noteId, count: 5, language: t('ai.language') === 'فارسی' ? 'fa' : 'fr' }),
+                            })
+                            const data = await res.json()
+                            if (res.ok && data.exercises) {
+                              toast.success(`${data.exercises.length} ${t('ai.generate.exercisesCreated') || 'exercices créés !'}`)
+                            } else {
+                              toast.error(data.error || 'Erreur')
+                            }
+                          } catch (e: any) {
+                            toast.error(e.message || 'Erreur')
+                          } finally {
+                            setGenerateLoading(null)
+                          }
+                        }}
+                        disabled={!!generateLoading}
+                        className="w-full py-3.5 bg-brand-accent text-white rounded-xl text-[10px] font-bold flex items-center justify-center gap-2 hover:opacity-90 transition-all shadow-lg shadow-brand-accent/20 uppercase tracking-[0.2em] disabled:opacity-50"
+                      >
+                        {generateLoading === 'exercises' ? <Loader2 size={14} className="animate-spin" /> : <><PenTool size={14} className="opacity-80" /> {t('ai.generate.generateExercises') || 'Générer'}</>}
+                      </button>
+                    </div>
+                  </div>
+                )}
+
                 {/* ── Personas IA ── */}
                 <PersonasPanel noteTitle={noteTitle} noteContent={noteContent} />
 

memento-note/components/note-editor/note-editor-toolbar.tsx

@@ -479,17 +479,6 @@ export function NoteEditorToolbar({ mode, onClose, onToggleAttachments, attachme
                   <Printer className="h-4 w-4 me-2" />
                   {t('richTextEditor.exportPdf') || 'Exporter en PDF'}
                 </DropdownMenuItem>
-                <DropdownMenuSeparator />
-                <DropdownMenuItem onClick={handleGenerateExercises} disabled={generatingExercises}>
-                  {generatingExercises
-                    ? <Loader2Icon className="h-4 w-4 me-2 animate-spin" />
-                    : <PenTool className="h-4 w-4 me-2 text-brand-accent" />
-                  }
-                  {generatingExercises
-                    ? (t('richTextEditor.exercisesLoading') || 'Génération...')
-                    : (t('richTextEditor.generateExercises') || 'Générer des exercices')
-                  }
-                </DropdownMenuItem>
                 <DropdownMenuItem onClick={openMarkdownImport}>
                   <FileUp className="h-4 w-4 me-2" />
                   {t('richTextEditor.importMarkdown')}