fix(caddy): prevent duplicate routes and make status/routes fetches independent

POST /api/caddy/routes now returns 409 if the hostname already exists,
preventing duplicate DB entries that cause Caddy's "ambiguous site definition" error.

loadCaddyRoutes uses Promise.allSettled so a failure in the status check
can no longer silently prevent the routes list from loading.

src/components/Settings.tsx

@@ -357,21 +357,25 @@ export default function Settings({ currentUser: _currentUser }: SettingsProps) {
   }
 
   async function loadCaddyRoutes() {
-    try {
-      const [statusRes, routesRes] = await Promise.all([
-        authFetch('/api/caddy/status'),
-        authFetch('/api/caddy/routes'),
-      ]);
-      if (statusRes.ok) {
-        const s = await statusRes.json();
+    const [statusResult, routesResult] = await Promise.allSettled([
+      authFetch('/api/caddy/status'),
+      authFetch('/api/caddy/routes'),
+    ]);
+    if (statusResult.status === 'fulfilled' && statusResult.value.ok) {
+      try {
+        const s = await statusResult.value.json();
         setCaddyStatus(s.available ? 'available' : 'unavailable');
+      } catch {
+        setCaddyStatus('unavailable');
       }
-      if (routesRes.ok) {
-        setCaddyRoutes(await routesRes.json());
-      }
-    } catch {
+    } else {
       setCaddyStatus('unavailable');
     }
+    if (routesResult.status === 'fulfilled' && routesResult.value.ok) {
+      try {
+        setCaddyRoutes(await routesResult.value.json());
+      } catch {}
+    }
   }
 
   async function handleAddRoute() {