feat: info icon on all PageHeader pages + Call Desk header restyled

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/pages/call-history.tsx

@@ -194,6 +194,7 @@ export const CallHistoryPage = () => {
                     title={isAdmin ? 'Call History' : 'My Call History'}
                     badge={filteredCalls.length}
                     subtitle={isAdmin ? `${completedCount} completed \u00B7 ${missedCount} missed` : `${completedCount} completed`}
+                    infoText={isAdmin ? 'All calls across all agents with recordings and dispositions.' : 'Your answered inbound and outbound calls.'}
                     controls={
                         <>
                             <div className="w-44">