fix type issues

this still breaks useFetch as the route returns null

src/nuxt.config.ts

@@ -90,5 +90,5 @@ export default defineNuxtConfig({
   },
   alias: {
     '#db': fileURLToPath(new URL('./server/database/', import.meta.url)),
-  }
-})
+  },
+});

src/server/api/session.get.ts

@@ -3,7 +3,7 @@ export default defineEventHandler(async (event) => {
 
   if (!session.data.userId) {
     // not logged in
-    return {};
+    return null;
   }
 
   const user = await Database.users.get(session.data.userId);