fix(providers): time out connection tests and guard undefined names

Apply a 15s AbortSignal timeout in fetchWithConnectionProxy when the
caller supplies none, so provider connection tests stop hanging and
exhausting the browser socket pool. Also make matchSearch return false
for falsy provider names instead of crashing the providers page.

src/app/(dashboard)/dashboard/providers/page.js

@@ -115,9 +115,11 @@ export default function ProvidersPage() {
     return () => unregisterSearch();
   }, [registerSearch, unregisterSearch]);
 
-  const matchSearch = (name) =>
-    !searchQuery.trim() ||
-    name.toLowerCase().includes(searchQuery.trim().toLowerCase());
+  const matchSearch = (name) => {
+    if (!searchQuery.trim()) return true;
+    if (!name) return false;
+    return name.toLowerCase().includes(searchQuery.trim().toLowerCase());
+  };
 
   const sortByPriority = (entries, authType) =>
     [...entries].sort(([ka, a], [kb, b]) => {