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/domains/DomainItem.tsx

@@ -1,5 +1,6 @@
 "use client";
 
+import React from "react";
 import type { Domain } from "@mosaic/shared";
 
 interface DomainItemProps {
@@ -8,7 +9,11 @@ interface DomainItemProps {
   onDelete?: (domain: Domain) => void;
 }
 
-export function DomainItem({ domain, onEdit, onDelete }: DomainItemProps): React.ReactElement {
+export const DomainItem = React.memo(function DomainItem({
+  domain,
+  onEdit,
+  onDelete,
+}: DomainItemProps): React.ReactElement {
   return (
     <div className="border rounded-lg p-4 hover:shadow-md transition-shadow">
       <div className="flex items-start justify-between">
@@ -52,4 +57,4 @@ export function DomainItem({ domain, onEdit, onDelete }: DomainItemProps): React
       </div>
     </div>
   );
-}
+});