Polish: per-route titles and a way to sign out

There was no sign-out control anywhere. Easy to miss when you develop
permanently signed in, and a stranded feeling for anyone on a shared machine.
Clearing the identity provider's session is sufficient — PIG holds no session
of its own — and the auth listener returns to sign-in without a reload. A hard
redirect follows regardless, so a failed provider call cannot leave a
half-signed-out interface.

Every route now sets its own document title. A single static title makes
browser history and a wall of tabs useless: every entry reads "pig" and nobody
can tell the margin view from the pipeline.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apps/web/src/pages/Accounts.tsx

@@ -6,6 +6,7 @@ import { useQuery } from '@tanstack/react-query';
 import { Building2 } from 'lucide-react';
 import { get, relativeTime } from '@/lib/api';
 import { Badge, ConfidenceBadge, EmptyState, Input, Skeleton } from '@/components/ui';
+import { usePageTitle } from '@/lib/title';
 
 interface Account {
   id: string;
@@ -20,6 +21,7 @@ interface Account {
 }
 
 export function Accounts() {
+  usePageTitle('Accounts');
   const [side, setSide] = useState<'all' | 'supply' | 'demand'>('all');
   const [query, setQuery] = useState('');