feat: SSE agent state, UCID fix, maint module, QA bug fixes

- Fix outbound disposition: store UCID from dial API response (root cause of silent disposition failure)
- SSE agent state: real-time Ozonetel state drives status toggle (ready/break/calling/in-call/acw)
- Maint module with OTP-protected endpoints (force-ready, unlock-agent, backfill, fix-timestamps)
- Maint OTP modal with PinInput component, keyboard shortcuts (Ctrl+Shift+R/U/B/T)
- Force-logout via SSE: admin unlock pushes force-logout to connected browsers
- Silence JsSIP debug flood, add structured lifecycle logging ([SIP], [DIAL], [DISPOSE], [AGENT-STATE])
- Centralize date formatting with IST-aware formatters across 11 files
- Fix call history: non-overlapping aggregates (completed/missed), correct timestamp display
- Auto-dismiss CallWidget ended/failed state after 3 seconds
- Remove floating "Helix Phone" idle badge from all pages
- Fix dead code in agent-state endpoint (auto-assign was unreachable after return)

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

src/components/layout/app-shell.tsx

@@ -3,7 +3,9 @@ import { useLocation } from 'react-router';
 import { Sidebar } from './sidebar';
 import { SipProvider } from '@/providers/sip-provider';
 import { CallWidget } from '@/components/call-desk/call-widget';
+import { MaintOtpModal } from '@/components/modals/maint-otp-modal';
 import { useAuth } from '@/providers/auth-provider';
+import { useMaintShortcuts } from '@/hooks/use-maint-shortcuts';
 
 interface AppShellProps {
     children: ReactNode;
@@ -12,6 +14,7 @@ interface AppShellProps {
 export const AppShell = ({ children }: AppShellProps) => {
     const { pathname } = useLocation();
     const { isCCAgent } = useAuth();
+    const { isOpen, activeAction, close } = useMaintShortcuts();
 
     // Heartbeat: keep agent session alive in Redis (CC agents only)
     useEffect(() => {
@@ -39,6 +42,7 @@ export const AppShell = ({ children }: AppShellProps) => {
                 <main className="flex flex-1 flex-col overflow-hidden">{children}</main>
                 {isCCAgent && pathname !== '/' && pathname !== '/call-desk' && <CallWidget />}
             </div>
+            <MaintOtpModal isOpen={isOpen} onOpenChange={(open) => !open && close()} action={activeAction} />
         </SipProvider>
     );
 };