fix: restore Expand/Minimize button in AI panel + dynamic width, note thumbnail SVG placeholder with emoji/letter

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

@@ -516,7 +516,8 @@ export function ContextualAIChat({
 
   return (
     <aside className={cn(
-      'border-l border-border/40 bg-background flex flex-col h-full w-full flex-shrink-0 z-10 transition-all duration-300',
+      '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,
     )}>
 
@@ -553,6 +554,16 @@ export function ContextualAIChat({
                 <Wand2 className="h-3.5 w-3.5" />
               </Button>
             )}
+            <Button
+              variant="ghost" size="icon"
+              className="h-7 w-7 text-muted-foreground hover:text-foreground"
+              onClick={() => setExpanded(e => !e)}
+              title={expanded ? t('ai.shrinkPanel') : t('ai.expandPanel')}
+            >
+              {expanded
+                ? <Minimize2 className="h-3.5 w-3.5" />
+                : <Maximize2 className="h-3.5 w-3.5" />}
+            </Button>
             <Button variant="ghost" size="icon" onClick={onClose} className="h-7 w-7 text-muted-foreground hover:text-foreground">
               <X className="h-3.5 w-3.5" />
             </Button>

memento-note/components/note-editor.tsx

@@ -899,7 +899,7 @@ export function NoteEditor({ note, readOnly = false, onClose, fullPage = false }
 
           {/* ── Side panel: AI Chat ── */}
           {aiOpen && (
-            <div className="w-[400px] h-full self-stretch border-l border-black/10 dark:border-white/10 bg-background flex flex-col z-50 shrink-0">
+            <div className="h-full self-stretch bg-background flex flex-col z-50 shrink-0">
               <ContextualAIChat
                 onClose={() => setAiOpen(false)}
                 noteTitle={title}

memento-note/components/notes-editorial-view.tsx

@@ -116,6 +116,63 @@ function EditorialNoteMenu({ note, onOpen, onOpenHistory }: {
   )
 }
 
+/** Deterministic hue from a string — consistent per note */
+function stringToHue(s: string): number {
+  let h = 0
+  for (let i = 0; i < s.length; i++) h = (h * 31 + s.charCodeAt(i)) & 0xffff
+  return h % 360
+}
+
+/** SVG thumbnail for notes without an image */
+function NoteThumbnailPlaceholder({ title, noteId }: { title: string; noteId: string }) {
+  // Try to extract the first emoji from the title
+  const emojiMatch = title.match(/\p{Emoji_Presentation}|\p{Emoji}\uFE0F/u)
+  const emoji = emojiMatch?.[0]
+  const letter = title.replace(/\p{Emoji_Presentation}|\p{Emoji}\uFE0F/gu, '').trim()[0]?.toUpperCase() || '?'
+  const hue = stringToHue(noteId)
+
+  return (
+    <div
+      className="h-full w-full flex items-center justify-center relative overflow-hidden"
+      style={{ background: `linear-gradient(145deg, hsl(${hue} 25% 94%) 0%, hsl(${hue} 18% 87%) 100%)` }}
+    >
+      {/* Decorative concentric circles */}
+      <svg
+        className="absolute inset-0 w-full h-full"
+        viewBox="0 0 224 168"
+        fill="none"
+        aria-hidden
+        style={{ color: `hsl(${hue} 30% 60%)` }}
+      >
+        <circle cx="112" cy="84" r="90" stroke="currentColor" strokeWidth="0.6" opacity="0.25" />
+        <circle cx="112" cy="84" r="64" stroke="currentColor" strokeWidth="0.6" opacity="0.2" />
+        <circle cx="112" cy="84" r="38" stroke="currentColor" strokeWidth="0.6" opacity="0.15" />
+        <line x1="22" y1="84" x2="202" y2="84" stroke="currentColor" strokeWidth="0.4" opacity="0.15" />
+        <line x1="112" y1="4" x2="112" y2="164" stroke="currentColor" strokeWidth="0.4" opacity="0.15" />
+      </svg>
+      {emoji ? (
+        <span
+          className="relative text-5xl leading-none select-none"
+          style={{ filter: `drop-shadow(0 2px 8px hsl(${hue} 40% 40% / 0.2))` }}
+        >
+          {emoji}
+        </span>
+      ) : (
+        <span
+          className="relative font-memento-serif font-bold select-none leading-none"
+          style={{
+            fontSize: '4.5rem',
+            color: `hsl(${hue} 35% 35%)`,
+            opacity: 0.35,
+          }}
+        >
+          {letter}
+        </span>
+      )}
+    </div>
+  )
+}
+
 export function NotesEditorialView({
   notes,
   onOpen,
@@ -166,7 +223,7 @@ export function NotesEditorialView({
                       className="w-full h-full object-cover mix-blend-multiply opacity-80 grayscale contrast-125 hover:grayscale-0 hover:opacity-100 transition-all duration-500"
                     />
                   ) : (
-                    <div className="h-full w-full bg-gradient-to-br from-muted/40 to-muted/10" aria-hidden />
+                    <NoteThumbnailPlaceholder title={title} noteId={note.id} />
                   )}
                 </div>
                 <div className="space-y-3 flex-1">