feat(brainstorm): Option D — toast + peek panel + navigation volontaire

3 points corrigés (plus d'éjection automatique du brainstorm):

1. Convertir idée → note:
   - Avant: setTimeout 2s → router.push (éjection forcée)
   - Après: toast.success persistant 10s + peek.open (drawer latéral)

2. Exporter session → note synthèse:
   - Avant: setTimeout 2s → router.push (éjection forcée)
   - Après: toast.success + peek.open

3. Voir note référencée:
   - Avant: router.push (éjection immédiate)
   - Après: peek.open (drawer latéral)

Comportement:
- Toast sonner avec bouton 'Ouvrir' (navigation volontaire)
- NotePeekPanel mode overlay (slide droite, lecture seule, KaTeX)
- Canvas brainstorm reste interactif derrière
- Bouton Maximize2 dans le peek → router.push (choix explicite)
- Anciens convertToast/exportToast supprimés (45 lignes JSX retirées)

memento-note/components/brainstorm/brainstorm-page.tsx

@@ -1,4 +1,5 @@
 'use client'
+import { toast } from 'sonner'
 
 import React, { useState, useMemo, useEffect, useRef, useCallback } from 'react'
 import { useRouter, useSearchParams } from 'next/navigation'
@@ -26,9 +27,11 @@ import {
   LayoutGrid,
   X,
   Edit2,
+  Maximize2,
 } from 'lucide-react'
 import dynamic from 'next/dynamic'
 import { useLanguage } from '@/lib/i18n'
+import { useNotePeek, NotePeekPanel } from '@/components/note-peek'
 import {
   useBrainstormSession,
   useBrainstormSessions,
@@ -76,6 +79,7 @@ const WAVE_COLORS: Record<number, { border: string; bg: string; text: string }>
 
 export function BrainstormPage() {
   const router = useRouter()
+  const peek = useNotePeek()
   const searchParams = useSearchParams()
   const { t, language } = useLanguage()
   const { data: authSession } = useSession()
@@ -132,8 +136,7 @@ export function BrainstormPage() {
   const renameSession = useRenameBrainstormSession(activeSessionId || '')
   const [impactToast, setImpactToast] = useState<{ notesEnriched: number; notesMarkedDry: number } | null>(null)
   const [exportError, setExportError] = useState<string | null>(null)
-  const [exportToast, setExportToast] = useState<{ noteTitle: string; notebookName: string } | null>(null)
-  const [convertToast, setConvertToast] = useState<{ noteTitle: string; noteId: string } | null>(null)
+
   const [remoteMove, setRemoteMove] = useState<{ ideaId: string; x: number; y: number; _seq: number } | null>(null)
   const [playbackIdeas, setPlaybackIdeas] = useState<any[] | null>(null)
   const [viewMode, setViewMode] = useState<'canvas' | 'list'>('canvas')
@@ -242,11 +245,15 @@ export function BrainstormPage() {
     try {
       const result = await convertIdea.mutateAsync(idea.id)
       if (result?.id) {
-        setConvertToast({ noteTitle: result.title || idea.title, noteId: result.id })
-        setTimeout(() => {
-          setConvertToast(null)
-          router.push(`/home?openNote=${result.id}`)
-        }, 2000)
+        toast.success(t('brainstorm.noteCreated') || 'Note created', {
+          description: result.title || idea.title,
+          action: {
+            label: t('notePeek.openFully') || 'Open',
+            onClick: () => router.push(`/home?openNote=${result.id}`),
+          },
+          duration: 10000,
+        })
+        peek.open(result.id)
       }
     } catch {}
   }
@@ -287,11 +294,15 @@ export function BrainstormPage() {
       const result = await exportBrainstorm.mutateAsync()
       if (result?.id) {
         const notebookName = result._notebookName || t('brainstorm.exportDefaultNotebookName')
-        setExportToast({ noteTitle: result.title || t('brainstorm.exportDefaultNoteTitle'), notebookName })
-        setTimeout(() => {
-          setExportToast(null)
-          router.push(`/home?openNote=${result.id}`)
-        }, 2000)
+        toast.success(t('brainstorm.noteCreated') || 'Note created', {
+          description: `${result.title || t('brainstorm.exportDefaultNoteTitle')} — ${notebookName}`,
+          action: {
+            label: t('notePeek.openFully') || 'Open',
+            onClick: () => router.push(`/home?openNote=${result.id}`),
+          },
+          duration: 10000,
+        })
+        peek.open(result.id)
         return
       }
       const impact = await finalizeBrainstorm.mutateAsync()
@@ -846,7 +857,7 @@ export function BrainstormPage() {
                             </div>
                             {ref.noteId && (
                               <button
-                                onClick={() => router.push(`/home?openNote=${ref.noteId}`)}
+                                onClick={() => ref.noteId && peek.open(ref.noteId)}
                                 className="shrink-0 px-2 py-1 text-[9px] font-bold uppercase tracking-wider rounded-lg bg-foreground/5 hover:bg-foreground/10 text-muted-foreground hover:text-foreground transition-all"
                               >
                                 {t('brainstorm.viewNote') || 'View'}
@@ -1124,49 +1135,15 @@ export function BrainstormPage() {
         )}
       </AnimatePresence>
 
-      <AnimatePresence>
-        {exportToast && (
-          <motion.div
-            initial={{ y: 100, opacity: 0 }}
-            animate={{ y: 0, opacity: 1 }}
-            exit={{ y: 100, opacity: 0 }}
-            className="fixed bottom-8 left-1/2 -translate-x-1/2 z-50 px-6 py-4 bg-emerald-600 text-white rounded-2xl shadow-2xl flex items-center gap-3 text-sm font-medium"
-          >
-            <Wind size={18} />
-            <div className="flex flex-col">
-              <span className="font-bold">{exportToast.noteTitle}</span>
-              <span className="text-[11px] text-emerald-100">
-                {t('brainstorm.exportNotebookPrefix')} {exportToast.notebookName}
-              </span>
-            </div>
-            <div className="ml-3 flex items-center gap-1.5 text-emerald-200 text-[10px]">
-              <div className="w-1.5 h-1.5 rounded-full bg-emerald-300 animate-pulse" />
-              {t('brainstorm.exportOpening')}
-            </div>
-          </motion.div>
-        )}
-      </AnimatePresence>
-
-      <AnimatePresence>
-        {convertToast && (
-          <motion.div
-            initial={{ y: 100, opacity: 0 }}
-            animate={{ y: 0, opacity: 1 }}
-            exit={{ y: 100, opacity: 0 }}
-            className="fixed bottom-8 left-1/2 -translate-x-1/2 z-50 px-6 py-4 bg-emerald-600 text-white rounded-2xl shadow-2xl flex items-center gap-3 text-sm font-medium"
-          >
-            <FileText size={18} />
-            <div className="flex flex-col">
-              <span className="font-bold">{convertToast.noteTitle}</span>
-              <span className="text-[11px] text-emerald-100">{t('brainstorm.noteCreated') || 'Note Created'}</span>
-            </div>
-            <div className="ml-3 flex items-center gap-1.5 text-emerald-200 text-[10px]">
-              <div className="w-1.5 h-1.5 rounded-full bg-emerald-300 animate-pulse" />
-              {t('brainstorm.exportOpening')}
-            </div>
-          </motion.div>
-        )}
-      </AnimatePresence>
+      {/* Peek panel — drawer latéral pour aperçu note sans quitter le brainstorm */}
+      <NotePeekPanel
+        note={peek.note}
+        blockId={peek.blockId}
+        loading={peek.loading}
+        mode="overlay"
+        onClose={peek.close}
+        onOpenFully={(n) => { router.push(`/home?openNote=${n.id}`); peek.close() }}
+      />
     </div>
   )
 }