Replace state blob with resource-oriented API endpoints

Split /api/v1/state into dedicated resource endpoints:
- /api/v1/operator, /api/v1/central-domain
- /api/v1/ddns/config, /api/v1/dns/settings
- /api/v1/dhcp/config (moved from /dnsmasq/dhcp/)
- /api/v1/nftables/config, /api/v1/haproxy/routes

Each page now talks to its own resource instead of deep-merging
a blob. Removes useConfig hook, CentralState type, and legacy
config methods.

web/src/components/DashboardComponent.tsx

@@ -12,9 +12,8 @@ import {
 import { useCloudflare } from '../hooks/useCloudflare';
 import { useDdns } from '../hooks/useDdns';
 import { useCentralStatus } from '../hooks/useCentralStatus';
-import { useConfig } from '../hooks';
 import { useVpn } from '../hooks/useVpn';
-import { secretsApi } from '../services/api';
+import { secretsApi, dnsSettingsApi, nftablesConfigApi } from '../services/api';
 import { usePageHelp } from '../hooks/usePageHelp';
 import type { DdnsRecordStatus } from '../services/api/networking';
 
@@ -22,8 +21,9 @@ export function DashboardComponent() {
   const { data: centralStatus, isLoading: statusLoading, restart: restartDaemon, isRestarting } = useCentralStatus();
   const { verification, isLoading: cfLoading } = useCloudflare();
   const { status: ddnsStatus, isLoadingStatus: ddnsLoading, trigger: triggerDdns, isTriggering } = useDdns();
-  const { config: globalConfig } = useConfig();
   const { config: vpnConfig } = useVpn();
+  const { data: dnsSettings } = useQuery({ queryKey: ['dns', 'settings'], queryFn: () => dnsSettingsApi.get() });
+  const { data: nftConfig } = useQuery({ queryKey: ['nftables', 'config'], queryFn: () => nftablesConfigApi.get() });
 
   const queryClient = useQueryClient();
   const { data: globalSecrets } = useQuery({
@@ -379,9 +379,9 @@ export function DashboardComponent() {
           <ul className="list-disc list-inside space-y-1 text-xs">
             <li>
               Set the router's DNS server to Wild Central
-              {globalConfig?.cloud?.dnsmasq?.ip && (
+              {dnsSettings?.ip && (
                 <span className="font-mono bg-muted px-1.5 py-0.5 rounded ml-1">
-                  {globalConfig.cloud.dnsmasq.ip}
+                  {dnsSettings.ip}
                 </span>
               )}
             </li>
@@ -391,7 +391,7 @@ export function DashboardComponent() {
                 { port: 443, proto: 'TCP', label: 'HTTPS' },
                 { port: 80, proto: 'TCP', label: 'HTTP' },
                 ...(vpnConfig?.enabled ? [{ port: vpnConfig.listenPort || 51820, proto: 'UDP', label: 'VPN' }] : []),
-                ...((globalConfig?.cloud?.nftables?.extraPorts ?? []) as { port: number; protocol?: string; label?: string }[])
+                ...((nftConfig?.extraPorts ?? []) as { port: number; protocol?: string; label?: string }[])
                   .map(ep => ({ port: ep.port, proto: (ep.protocol || 'tcp').toUpperCase(), label: ep.label || '' })),
               ].map((p, i) => (
                 <span key={i}>