fix: Dashboard blank page — move state declarations before use

SERVICES was computed on line 33 using activeServiceIds which was not
declared until line 36. In strict JS, const is not hoisted — this threw
a ReferenceError on mount, crashing the component and showing a blank page.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

webui/src/pages/Dashboard.jsx

@@ -24,6 +24,10 @@ function Dashboard({ isOnline }) {
   const { domain = 'cell', cell_name = 'mycell', effective_domain, domain_mode = 'lan' } = useConfig();
   const svcDomain = (domain_mode !== 'lan' && effective_domain) ? effective_domain : domain;
   const proto = domain_mode === 'lan' ? 'http' : 'https';
+  const [cellStatus, setCellStatus] = useState(null);
+  const [servicesStatus, setServicesStatus] = useState(null);
+  const [activeServiceIds, setActiveServiceIds] = useState(new Set());
+
   const ALL_SERVICE_LINKS = [
     { id: null,       name: 'Cell Home', url: domain_mode === 'lan' ? `http://${cell_name}.${domain}` : `https://${svcDomain}`, desc: 'Main UI — no login needed' },
     { id: 'calendar', name: 'Calendar',  url: `${proto}://calendar.${svcDomain}`,  desc: 'Use your configured account credentials' },
@@ -31,9 +35,6 @@ function Dashboard({ isOnline }) {
     { id: 'email',    name: 'Webmail',   url: `${proto}://mail.${svcDomain}`,      desc: 'Use your configured account credentials' },
   ];
   const SERVICES = ALL_SERVICE_LINKS.filter(s => s.id === null || activeServiceIds.has(s.id));
-  const [cellStatus, setCellStatus] = useState(null);
-  const [servicesStatus, setServicesStatus] = useState(null);
-  const [activeServiceIds, setActiveServiceIds] = useState(new Set());
   const [isLoading, setIsLoading] = useState(true);
   const [serviceControls, setServiceControls] = useState({});