feat(sessions): show a pending-question indicator on session rows

Adds a per-session pending-question badge to sidebar rows, driven by the
live directory-store question state through a dedicated per-session
subscription channel so unrelated streaming never re-renders rows.

Collapsed parent rows roll up pending questions of hidden descendants
from their owning directory stores without bootstrapping them. Question
state is cloned on session delete/archive so badges clear when sessions
disappear. Adds the questionChangeCallbacks sync performance counter,
i18n keys for all locales, and unit tests for the subscription channel
and scope selection.

Fixes #2634

packages/ui/src/components/session/sidebar/SessionNodeItem.tsx

@@ -22,11 +22,11 @@ import { isSessionPinned, type SessionPinnedTarget } from '@/stores/useSessionPi
 import { Icon } from "@/components/icon/Icon";
 import { buildExportFilename, downloadAsMarkdown, formatSessionAsMarkdown, getExportRevealLabelKey, revealExportedMarkdown, saveAsMarkdownDesktop } from '@/lib/exportSession';
 import type { ChildSessionExport } from '@/lib/exportSession';
-import { buildSessionMessageRecordsSnapshot, useDirectoryStore, useGlobalSessionStatus, useSessionPermissions } from '@/sync/sync-context';
+import { buildSessionMessageRecordsSnapshot, useDirectoryStore, useGlobalSessionStatus, useSessionPermissions, useSessionQuestionCount } from '@/sync/sync-context';
 import { useSync } from '@/sync/use-sync';
 import { useViewportStore, viewportSessionKey } from '@/sync/viewport-store';
 import { DraggableSessionRow } from './sessionFolderDnd';
-import { nodeContainsSessionId, nodeHasPinnedMembershipChange } from './sessionNodeItemUtils';
+import { nodeContainsSessionId, nodeHasPinnedMembershipChange, selectQuestionBadgeSessionScopes } from './sessionNodeItemUtils';
 import type { SessionNodeChildRenderExtras, SessionNodeRenderExtras } from './sessionNodeItemUtils';
 import type { SessionNode } from './types';
 import { formatProjectLabel, formatSessionCompactDateLabel, formatSessionDateLabel, normalizePath, renderHighlightedText } from './utils';
@@ -470,6 +470,11 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
   // expand the other. Matches the format of menuInstanceKey.
   const expansionKey = menuInstanceKey;
   const isExpanded = hasSessionSearchQuery ? true : expandedParents.has(expansionKey);
+  const questionBadgeSessionScopes = React.useMemo(
+    () => selectQuestionBadgeSessionScopes(node, isExpanded, sessionDirectory),
+    [isExpanded, node, sessionDirectory],
+  );
+  const pendingQuestionCount = useSessionQuestionCount(questionBadgeSessionScopes);
   const isSubtaskSession = Boolean((resolvedSession as Session & { parentID?: string | null }).parentID);
   const unseenCount = useSessionUnseenCount(session.id);
   const needsAttention = unseenCount > 0 && (!isSubtaskSession || notifyOnSubtasks);
@@ -676,6 +681,9 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
   }
 
   const pendingPermissionCount = sessionPermissions.length;
+  const pendingQuestionLabel = pendingQuestionCount === 1
+    ? t('sessions.sidebar.session.status.questionPendingSingle')
+    : t('sessions.sidebar.session.status.questionPendingMany', { count: pendingQuestionCount });
   const showUnreadStatus = !isMovingToWorktree && !isStreaming && needsAttention && !isActive;
   const showStatusMarker = isStreaming || showUnreadStatus;
   // Both states are the same static dot; only the color separates "running"
@@ -1292,6 +1300,12 @@ function SessionNodeItemComponent(props: Props): React.ReactNode {
                           <span className="leading-none">{pendingPermissionCount}</span>
                         </span>
                       ) : null}
+                      {pendingQuestionCount > 0 ? (
+                        <span className="inline-flex items-center gap-1 rounded bg-status-info/10 px-1 py-0.5 text-[0.7rem] text-status-info flex-shrink-0" title={pendingQuestionLabel} aria-label={pendingQuestionLabel}>
+                          <Icon name="question" className="h-3 w-3" />
+                          <span className="leading-none">{pendingQuestionCount}</span>
+                        </span>
+                      ) : null}
                     </div>
                   </button>
                 </TooltipTrigger>