refactor: improve ActivityTimeline and team mention entry sorting

- Updated ActivityTimeline to conditionally set `canBeLive`, `isTeamAlive`, `leadActivity`, and `leadContextUpdatedAt` based on the current lead session.
- Enhanced sorting of team mention entries in useStableTeamMentionMeta by introducing a comparison function for better organization of team data.

src/renderer/components/team/activity/ActivityTimeline.tsx

@@ -510,6 +510,9 @@ export const ActivityTimeline = React.memo(function ActivityTimeline({
         (() => {
           const { group } = pinnedThoughtGroup;
           const firstThought = group.thoughts[0];
+          const pinnedCanBeLive = currentLeadSessionId
+            ? firstThought.leadSessionId === currentLeadSessionId
+            : true;
           const info = memberInfo.get(firstThought.from);
           const itemKey = getThoughtGroupKey(group);
           const stableKey = itemKey;
@@ -519,10 +522,10 @@ export const ActivityTimeline = React.memo(function ActivityTimeline({
               key={itemKey}
               group={group}
               memberColor={info?.color}
-              canBeLive={true}
-              isTeamAlive={isTeamAlive}
-              leadActivity={leadActivity}
-              leadContextUpdatedAt={leadContextUpdatedAt}
+              canBeLive={pinnedCanBeLive}
+              isTeamAlive={pinnedCanBeLive ? isTeamAlive : undefined}
+              leadActivity={pinnedCanBeLive ? leadActivity : undefined}
+              leadContextUpdatedAt={pinnedCanBeLive ? leadContextUpdatedAt : undefined}
               isNew={newItemKeys.has(itemKey)}
               onVisible={onMessageVisible}
               zebraShade={zebraShadeSet.has(0)}
@@ -591,9 +594,6 @@ export const ActivityTimeline = React.memo(function ActivityTimeline({
                 group={group}
                 memberColor={info?.color}
                 canBeLive={false}
-                isTeamAlive={isTeamAlive}
-                leadActivity={leadActivity}
-                leadContextUpdatedAt={leadContextUpdatedAt}
                 isNew={newItemKeys.has(itemKey)}
                 onVisible={onMessageVisible}
                 zebraShade={zebraShadeSet.has(realIndex)}

src/renderer/hooks/useStableTeamMentionMeta.ts

@@ -12,18 +12,27 @@ interface TeamMentionEntry {
   deletedAt: string;
 }
 
+function compareTeamMentionEntries(a: TeamMentionEntry, b: TeamMentionEntry): number {
+  return (
+    a.teamName.localeCompare(b.teamName, undefined, { sensitivity: 'base' }) ||
+    a.displayName.localeCompare(b.displayName, undefined, { sensitivity: 'base' })
+  );
+}
+
 export interface TeamMentionMeta {
   teamNames: string[];
   teamColorByName: ReadonlyMap<string, string>;
 }
 
 function buildTeamMentionEntries(teams: readonly TeamSummary[]): TeamMentionEntry[] {
-  return teams.map((team) => ({
-    teamName: team.teamName ?? '',
-    displayName: team.displayName ?? '',
-    color: team.color ?? '',
-    deletedAt: team.deletedAt ?? '',
-  }));
+  return teams
+    .map((team) => ({
+      teamName: team.teamName ?? '',
+      displayName: team.displayName ?? '',
+      color: team.color ?? '',
+      deletedAt: team.deletedAt ?? '',
+    }))
+    .sort(compareTeamMentionEntries);
 }
 
 function areTeamMentionEntriesEqual(