fix: title textarea auto-resize (no overflow), auto-title 10-word check + toast feedback, AI expand = fixed overlay (no compress)

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

@@ -515,11 +515,21 @@ export function ContextualAIChat({
 
 
   return (
-    <aside className={cn(
-      'border-l border-border/40 bg-background flex flex-col h-full flex-shrink-0 z-10 transition-all duration-300',
-      expanded ? 'w-[560px]' : 'w-[360px]',
-      className,
-    )}>
+    <>
+      {/* Backdrop when expanded */}
+      {expanded && (
+        <div
+          className="fixed inset-0 z-[199] bg-black/10 dark:bg-black/20 backdrop-blur-[1px]"
+          onClick={() => setExpanded(false)}
+        />
+      )}
+      <aside className={cn(
+        'border-l border-border/40 bg-background flex flex-col flex-shrink-0 z-10 transition-all duration-300',
+        expanded
+          ? 'fixed right-0 top-0 h-screen w-[640px] z-[200] shadow-2xl border-l'
+          : 'h-full w-[360px]',
+        !expanded && className,
+      )}>
 
       {/* ── Header ─────────────────────────────────────────── */}
       <div className="px-5 pt-5 pb-4 border-b border-border/40 shrink-0">
@@ -1386,6 +1396,7 @@ export function ContextualAIChat({
         </div>
       )}
     </aside>
+    </>
   )
 }