fix: align activity indicator with composer input width

Wrap ActivityIndicator in the same mx-auto max-w-3xl container as the
text input so the "Analyzing…" label and Stop button stay within the
input's boundaries instead of spanning the full window width.

src/components/chat/view/subcomponents/ActivityIndicator.tsx

@@ -52,8 +52,8 @@ export default function ActivityIndicator({ activity, onAbort }: ActivityIndicat
     : t('claudeStatus.elapsed.minutesSeconds', { minutes, seconds, defaultValue: '{{minutes}}m {{seconds}}s' });
 
   return (
-    <div className="animate-in fade-in mb-2 w-full duration-300">
-      <div className="mx-auto flex max-w-4xl items-center gap-2 px-1">
+    <div className="animate-in fade-in mb-2 duration-300">
+      <div className="flex items-center gap-2 px-1">
         <span className="h-1.5 w-1.5 shrink-0 animate-pulse rounded-full bg-primary" aria-hidden />
         <Shimmer className="text-xs font-medium">{`${label}…`}</Shimmer>
         <span className="text-xs tabular-nums text-muted-foreground/60">{elapsedLabel}</span>

src/components/chat/view/subcomponents/ChatComposer.tsx

@@ -199,7 +199,9 @@ export default function ChatComposer({
   return (
     <div className="chat-composer-shell flex-shrink-0 px-2 pb-2 pt-0 sm:px-4 sm:pb-4 md:px-4 md:pb-6">
       {!hasPendingPermissions && (
-        <ActivityIndicator activity={activity} onAbort={onAbortSession} />
+        <div className="mx-auto max-w-3xl">
+          <ActivityIndicator activity={activity} onAbort={onAbortSession} />
+        </div>
       )}
 
       {pendingPermissionRequests.length > 0 && (