feat: call desk redesign — 2-panel layout, collapsible sidebar, inline AI, ringtone

- Collapsible sidebar with Jotai atom (icon-only mode, persisted to localStorage)
- 2-panel call desk: worklist (60%) + context panel (40%) with AI + Lead 360 tabs
- Inline AI call prep card — known lead summary or unknown caller script
- Active call card with compact Answer/Decline buttons
- Worklist panel with human-readable labels, priority badges, click-to-select
- Context panel auto-switches to Lead 360 when lead selected or call incoming
- Browser ringtone via Web Audio API on incoming calls
- Sonner + Untitled UI IconNotification for toast system
- apiClient pattern: centralized post/get/graphql with auto-toast on errors
- Remove duplicate avatar from top bar, hide floating widget on call desk
- Fix Link routing in collapsed sidebar (was using <a> causing full page reload)
- Fix GraphQL field names: adStatus→status, platformUrl needs subfield selection
- Silent mode for DataProvider queries to prevent toast spam

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

src/components/layout/app-shell.tsx

@@ -18,7 +18,7 @@ export const AppShell = ({ children }: AppShellProps) => {
             <div className="flex min-h-screen bg-primary">
                 <Sidebar activeUrl={pathname} />
                 <main className="flex flex-1 flex-col overflow-auto">{children}</main>
-                {isCCAgent && <CallWidget />}
+                {isCCAgent && pathname !== '/' && pathname !== '/call-desk' && <CallWidget />}
             </div>
         </SipProvider>
     );