fix: LocalKeyGate popup buttons now clickable

- Use React Portal to render popup to document.body
- Fixes stacking context issue that blocked button clicks
- Added mounted state for proper SSR hydration
- Increased z-index to 99999 with explicit pointer-events

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/auth/LocalKeyGate.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useEffect, useMemo, useState } from 'react';
+import { createPortal } from 'react-dom';
 import { isLocalMode } from '@/config/runtime';
 import { apiKeyService } from '@/services/storage/apiKeys';
 
@@ -30,6 +31,11 @@ const buttonStyle: React.CSSProperties = {
 export function LocalKeyGate({ children }: LocalKeyGateProps) {
   const isLocal = useMemo(() => isLocalMode(), []);
   const [hasKeys, setHasKeys] = useState(() => (!isLocal) || apiKeyService.hasUserKeys());
+  const [mounted, setMounted] = useState(false);
+
+  useEffect(() => {
+    setMounted(true);
+  }, []);
 
   useEffect(() => {
     if (!isLocal) return;
@@ -47,21 +53,18 @@ export function LocalKeyGate({ children }: LocalKeyGateProps) {
   }
 
   const openApiKeySettings = () => {
-    if (typeof window !== 'undefined') {
     window.dispatchEvent(new CustomEvent('settings:open', { detail: { tab: 'apikeys' } }));
-    }
   };
 
-  return (
-    <>
-      {children}
+  const popupContent = (
     <div
       style={{
         position: 'fixed',
         top: 24,
         right: 24,
         maxWidth: 420,
-          zIndex: 9999
+        zIndex: 99999,
+        pointerEvents: 'auto'
       }}
     >
       <div style={panelStyle}>
@@ -73,9 +76,7 @@ export function LocalKeyGate({ children }: LocalKeyGateProps) {
           </p>
         </div>
         <div style={{ display: 'flex', gap: 12, justifyContent: 'center', flexWrap: 'wrap' }}>
-            <button style={buttonStyle} onClick={() => {
-              openApiKeySettings();
-            }}>
+          <button style={buttonStyle} onClick={openApiKeySettings}>
             Open API Key Settings
           </button>
           <button
@@ -87,6 +88,12 @@ export function LocalKeyGate({ children }: LocalKeyGateProps) {
         </div>
       </div>
     </div>
+  );
+
+  return (
+    <>
+      {children}
+      {mounted && createPortal(popupContent, document.body)}
     </>
   );
 }