feat: notification bell in PageHeader + remove wasted top bar row for supervisors

- PageHeader: renders NotificationBell when isAdmin — bell now appears
  on every page that uses PageHeader (leads, contacts, appointments,
  patients, call history, missed calls, call recordings, live monitor,
  team performance, settings)
- app-shell: top bar row only renders for agents (network indicator +
  status toggle). Supervisors no longer see a wasted empty row.
- Call Recordings: TopBar → PageHeader with badge + info icon
- Live Monitor: TopBar → PageHeader with badge + info icon
- Team Performance: TopBar → PageHeader with info icon
- Settings: TopBar → PageHeader with info icon
- Missed Calls: underline tabs → custom pills (consistent with all pages)
- Desktop overlay app-shell synced with same changes

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

src/pages/settings.tsx

@@ -9,7 +9,7 @@ import {
     faPalette,
     faShieldHalved,
 } from '@fortawesome/pro-duotone-svg-icons';
-import { TopBar } from '@/components/layout/top-bar';
+import { PageHeader } from '@/components/layout/page-header';
 import { SectionCard } from '@/components/setup/section-card';
 import {
     SETUP_STEP_NAMES,
@@ -50,7 +50,7 @@ export const SettingsPage = () => {
 
     return (
         <div className="flex flex-1 flex-col overflow-hidden">
-            <TopBar title="Settings" subtitle="Configure your hospital workspace" />
+            <PageHeader title="Settings" infoText="Configure your hospital workspace." />
 
             <div className="flex-1 overflow-y-auto p-8">
                 <div className="mx-auto max-w-5xl">