fix: stable catalog reference, pin windows runner

- Providers.tsx: wrap catalog in useMemo so filtered memo doesn't
  re-run on every render when catalogQuery.data is undefined
- ci.yml: pin windows-latest -> windows-2025 ahead of June 15 redirect

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

.github/workflows/ci.yml

@@ -92,7 +92,7 @@ jobs:
             target: x86_64-apple-darwin
             binary: anyllm_proxy
           # Windows x86_64
-          - os: windows-latest
+          - os: windows-2025
             target: x86_64-pc-windows-msvc
             binary: anyllm_proxy.exe
     runs-on: ${{ matrix.os }}

crates/proxy/admin-ui/src/tabs/providers/Providers.tsx

@@ -307,7 +307,7 @@ export default function Providers() {
   const [search, setSearch] = useState('')
   const [pendingDelete, setPendingDelete] = useState<ManagedBackend | null>(null)
 
-  const catalog = catalogQuery.data ?? []
+  const catalog = useMemo(() => catalogQuery.data ?? [], [catalogQuery.data])
   const managed = useMemo(() => managedQuery.data?.backends ?? [], [managedQuery.data])
 
   // Backend count per provider_id