feat(insights): sidebar en mode overlay sur /insights — pleine largeur

AGENTS.md: 'pas la liste carnets sur /insights'
- sidebar.tsx: isImmersiveRoute sur /insights → fixed overlay au lieu de relative
- Toutes tailles d'écran: sidebar caché par défaut, s'ouvre en drawer
- Bouton hamburger visible sur desktop + mobile (pas lg:hidden)
- Insights prend 100% de la largeur → graphe + dashboard plus spacious

memento-note/components/sidebar.tsx

@@ -702,6 +702,7 @@ export function Sidebar({ className, user }: { className?: string; user?: any })
 
   const isRemindersRoute = pathname === '/home' && searchParams.get('reminders') === '1'
   const isSharedRoute = pathname === '/home' && searchParams.get('shared') === '1'
+  const isImmersiveRoute = pathname === '/insights'
   const isNotebooksRoute =
     (pathname === '/home' || pathname.startsWith('/notes')) &&
     !pathname.startsWith('/settings') &&
@@ -1157,11 +1158,16 @@ export function Sidebar({ className, user }: { className?: string; user?: any })
 
       <aside
         className={cn(
-          // Mobile: fixed overlay, slide in/out
-          'fixed inset-y-0 start-0 z-[70] md:relative md:z-auto',
+          // Sur /insights : sidebar en overlay (toutes tailles d'écran)
+          // Ailleurs : overlay sur mobile, relative sur desktop
+          isImmersiveRoute
+            ? 'fixed inset-y-0 start-0 z-[70]'
+            : 'fixed inset-y-0 start-0 z-[70] md:relative md:z-auto',
           'h-full min-h-0 w-80 xl:w-[22rem] 2xl:w-[26rem] shrink-0 flex flex-row overflow-hidden',
           'transition-transform duration-300 ease-in-out',
-          isMobileOpen ? 'translate-x-0 shadow-2xl' : '-translate-x-full md:translate-x-0',
+          isImmersiveRoute
+            ? (isMobileOpen ? 'translate-x-0 shadow-2xl' : '-translate-x-full')
+            : (isMobileOpen ? 'translate-x-0 shadow-2xl' : '-translate-x-full md:translate-x-0'),
           'border-e border-border/40 bg-white/95 md:bg-white/30 backdrop-blur-md sidebar-shadow dark:border-white/6 dark:bg-[#151515] dark:backdrop-blur-none',
           className
         )}