fix(CQ-WEB-8): Add React.memo to performance-sensitive components

Wrap 7 list-item/card components with React.memo to prevent unnecessary
re-renders when parent components update but props remain unchanged:
- TaskItem (task lists)
- EventCard (calendar views)
- EntryCard (knowledge base)
- WorkspaceCard (workspace list)
- TeamCard (team list)
- DomainItem (domain list)
- ConnectionCard (federation connections)

All are pure components rendered inside .map() loops that depend solely
on their props for rendering output.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/components/workspace/WorkspaceCard.tsx

@@ -1,3 +1,4 @@
+import React from "react";
 import type { Workspace } from "@mosaic/shared";
 import { WorkspaceMemberRole } from "@mosaic/shared";
 import Link from "next/link";
@@ -22,7 +23,7 @@ const roleLabels: Record<WorkspaceMemberRole, string> = {
   [WorkspaceMemberRole.GUEST]: "Guest",
 };
 
-export function WorkspaceCard({
+export const WorkspaceCard = React.memo(function WorkspaceCard({
   workspace,
   userRole,
   memberCount,
@@ -58,4 +59,4 @@ export function WorkspaceCard({
       </div>
     </Link>
   );
-}
+});