fix: resolve Apollo cache warning for TeamStats embedded objects

Add merge: true policy for Team.stats so InMemoryCache merges partial
TeamStats selections (e.g. search page) with fuller ones (team/stats pages)
instead of replacing and losing fields. Also align stats page query to
include goalDiff for consistency.

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

lib/graphql/client.ts

@@ -7,7 +7,11 @@ let client: InstanceType<typeof ApolloClient> | null = null
 function createClient() {
   return new ApolloClient({
     link: new HttpLink({ uri: '/api/graphql' }),
-    cache: new InMemoryCache(),
+    cache: new InMemoryCache({
+      typePolicies: {
+        Team: { fields: { stats: { merge: true } } },
+      },
+    }),
     defaultOptions: { watchQuery: { fetchPolicy: 'cache-and-network' } },
   })
 }