feat(tui): collapse completed todo panel on turn end

ui-tui/src/components/messageLine.tsx

@@ -38,7 +38,14 @@ export const MessageLine = memo(function MessageLine({
   const thinking = msg.thinking?.trim() ?? ''
 
   if (msg.kind === 'trail' && msg.todos?.length) {
-    return <TodoPanel incomplete={msg.todoIncomplete} t={t} todos={msg.todos} />
+    return (
+      <TodoPanel
+        defaultCollapsed={msg.todoCollapsedByDefault}
+        incomplete={msg.todoIncomplete}
+        t={t}
+        todos={msg.todos}
+      />
+    )
   }
 
   if (msg.kind === 'trail' && (msg.tools?.length || tools.length || thinking)) {

ui-tui/src/components/todoPanel.tsx

@@ -14,12 +14,14 @@ const rowColor = (t: Theme, status: TodoItem['status']) => {
 
 export const TodoPanel = memo(function TodoPanel({
   collapsed,
+  defaultCollapsed = false,
   incomplete = false,
   onToggle,
   t,
   todos
 }: {
   collapsed?: boolean
+  defaultCollapsed?: boolean
   incomplete?: boolean
   onToggle?: () => void
   t: Theme
@@ -28,7 +30,7 @@ export const TodoPanel = memo(function TodoPanel({
   // Fallback local state for archived todos in transcript where there's no
   // external controller. Live TodoPanel passes collapsed+onToggle from the
   // turn store so clicks still work there.
-  const [localCollapsed, setLocalCollapsed] = useState(false)
+  const [localCollapsed, setLocalCollapsed] = useState(defaultCollapsed)
   const isControlled = typeof collapsed === 'boolean'
   const effectiveCollapsed = isControlled ? collapsed : localCollapsed