Fix leftnav navigation regression and useProxySettings initial state

The leftnav was updated to emit page="api-reference" but only "api_ref"
was in LEGACY_REDIRECTS, causing clicks to fall through to the default
Usage page. Add "api-reference" entry to the redirect map. Also include
LITELLM_UI_API_DOC_BASE_URL in the hook's initial state to avoid a
brief flash of incorrect base URL.

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

ui/litellm-dashboard/src/app/(dashboard)/hooks/proxySettings/useProxySettings.ts

@@ -7,6 +7,7 @@ export default function useProxySettings() {
   const [proxySettings, setProxySettings] = useState({
     PROXY_BASE_URL: "",
     PROXY_LOGOUT_URL: "",
+    LITELLM_UI_API_DOC_BASE_URL: null as string | null,
   });
 
   useEffect(() => {

ui/litellm-dashboard/src/app/page.tsx

@@ -81,6 +81,7 @@ interface ProxySettings {
  */
 const LEGACY_REDIRECTS: Record<string, string> = {
   api_ref: "api-reference",
+  "api-reference": "api-reference",
 };
 
 function CreateKeyPageContent() {