feat: redesign nav — home shows public links, user menu with dropdown

- Remove Public Directory tab; public links now show on home page
- Rename Private Links to My Links
- Add right-aligned user menu with hover dropdown (Profile, Settings, Admin, Logout)
- Show admin badge next to username when role=admin
- Show Sign In button when not logged in
- Admin tab only visible to admins
- New GET /api/auth/me endpoint returns current user from session
- useCurrentUser hook for auth state in React
- CSS-only hover dropdown with fade-in animation
- Placeholder pages for Profile and Settings

worker/index.ts

@@ -1,5 +1,6 @@
 import type { Env } from './env';
 import { withPrivateNoStoreHeaders } from './lib/responses';
+import { handleAuthApi } from './routes/api.auth';
 import { handleDevAuth } from './routes/api.dev-auth';
 import { handleLinksApi } from './routes/api.links';
 import { handlePromotionsApi } from './routes/api.promotions';
@@ -35,6 +36,10 @@ export default {
     }
 
     if (url.pathname.startsWith('/api/')) {
+      const authResponse = await handleAuthApi(request, env);
+      if (authResponse) {
+        return withPrivateHostNoStoreHeaders(url, authResponse, env.PRIVATE_HOST);
+      }
       const devAuthResponse = await handleDevAuth(request, env);
       if (devAuthResponse) {
         return withPrivateHostNoStoreHeaders(url, devAuthResponse, env.PRIVATE_HOST);

worker/routes/api.auth.ts

@@ -0,0 +1,29 @@
+import { getCurrentUser } from '../auth';
+import type { Env } from '../env';
+
+export async function handleAuthApi(request: Request, env: Env): Promise<Response | null> {
+  const url = new URL(request.url);
+
+  if (url.pathname !== '/api/auth/me') {
+    return null;
+  }
+
+  if (request.method !== 'GET') {
+    return Response.json({ error: 'Method not allowed' }, { status: 405 });
+  }
+
+  const user = await getCurrentUser(request, env);
+  if (!user) {
+    return Response.json({ user: null }, { status: 200 });
+  }
+
+  return Response.json({
+    user: {
+      id: user.id,
+      email: user.email,
+      name: user.name,
+      imageUrl: user.imageUrl,
+      role: user.role,
+    },
+  });
+}