feat(dashboard): tableau de bord Second Brain configurable avec chargement progressif

Briefing granulaire, pistes rapides puis enrichissement async, layout persisté v5,
suggestions agents, intégration Gmail et navigation sidebar alignée sur /home.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/components/home-client.tsx

@@ -34,6 +34,7 @@ import { StudyPlannerDialog } from '@/components/wizard/study-planner-dialog'
 import { NotebookOrganizerDialog } from '@/components/wizard/notebook-organizer-dialog'
 import { toast } from 'sonner'
 import { AnimatePresence, motion } from 'motion/react'
+import { isDashboardHomeRoute } from '@/lib/dashboard/home-route'
 
 
 type SortOrder = 'newest' | 'oldest' | 'alpha' | 'manual'
@@ -58,6 +59,10 @@ const OrganizeNotebookDialog = dynamic(
   () => import('@/components/organize-notebook-dialog').then(m => ({ default: m.OrganizeNotebookDialog })),
   { ssr: false }
 )
+const DashboardView = dynamic(
+  () => import('@/components/dashboard-view').then(m => ({ default: m.DashboardView })),
+  { ssr: false }
+)
 const NotebookSiteDialog = dynamic(
   () => import('@/components/wizard/notebook-site-dialog').then(m => ({ default: m.NotebookSiteDialog })),
   { ssr: false }
@@ -225,15 +230,12 @@ export function HomeClient({
   }, [])
 
   // Sidebar carnet / inbox: fermer l'éditeur plein écran (comme la ref. architectural-grid)
+  // On GARDE forceList dans l'URL pour distinguer "liste" du "dashboard"
   useEffect(() => {
     if (searchParams.get('forceList') === '1') {
       setEditingNote(null)
-      const params = new URLSearchParams(searchParams.toString())
-      params.delete('forceList')
-      const newUrl = params.toString() ? `/home?${params.toString()}` : '/home'
-      router.replace(newUrl, { scroll: false })
     }
-  }, [searchParams, router])
+  }, [searchParams])
 
   const fetchNotesForCurrentView = useCallback(
     async (options?: { silent?: boolean }) => {
@@ -821,6 +823,16 @@ export function HomeClient({
     emitNoteChange({ type: 'updated', note: savedNote })
   }, [])
 
+  // Show dashboard when no active filter/view params
+  const showDashboard = !editingNote && isDashboardHomeRoute('/home', searchParams)
+
+  const handleDashboardNoteSelect = useCallback((noteId: string, notebookId: string | null) => {
+    const params = new URLSearchParams()
+    params.set('openNote', noteId)
+    if (notebookId) params.set('notebook', notebookId)
+    router.push(`/home?${params.toString()}`)
+  }, [router])
+
   return (
     <div
       className={cn(
@@ -838,6 +850,8 @@ export function HomeClient({
             fullPage
           />
         </div>
+      ) : showDashboard ? (
+        <DashboardView onNoteSelect={handleDashboardNoteSelect} />
       ) : (
         <div className="flex-1 overflow-y-auto min-h-0 bg-memento-paper dark:bg-background flex flex-col">
           <div