Fix stale conversation sync labels on mobile

src/lib/boss-projections.ts

@@ -180,6 +180,20 @@ export function formatTimestampLabel(value?: string, fallback = "刚刚") {
   return shanghaiDayFormatter.format(date);
 }
 
+const STALE_CONTEXT_SYNC_LABEL = "待同步";
+const STALE_CONTEXT_REPLY_THRESHOLD_MS = 7 * 24 * 60 * 60_000;
+
+function formatConversationLatestReplyLabel(value: string, hasVisibleContext: boolean) {
+  if (hasVisibleContext && value.includes("T")) {
+    const date = new Date(value);
+    const diff = Date.now() - date.getTime();
+    if (!Number.isNaN(date.getTime()) && diff >= STALE_CONTEXT_REPLY_THRESHOLD_MS) {
+      return STALE_CONTEXT_SYNC_LABEL;
+    }
+  }
+  return formatTimestampLabel(value);
+}
+
 function compareSnapshots(a: ThreadContextSnapshot, b: ThreadContextSnapshot) {
   if (a.mustFinishBeforeCompaction !== b.mustFinishBeforeCompaction) {
     return a.mustFinishBeforeCompaction ? -1 : 1;
@@ -386,7 +400,10 @@ function buildConversationItem(state: BossState, project: Project): Conversation
     topPinnedLabel,
     manualPinned: Boolean(project.pinned && !project.systemPinned),
     latestReplyAt: latestConversationActivityAt,
-    latestReplyLabel: formatTimestampLabel(latestConversationActivityAt),
+    latestReplyLabel: formatConversationLatestReplyLabel(
+      latestConversationActivityAt,
+      Boolean(topThread),
+    ),
     unreadCount: project.unreadCount,
     riskLevel: project.riskLevel,
     activeDeviceCount: devices.length,