fix: resolve relationship error in admin dashboard

- Fetched api_usage and profiles separately to avoid Supabase join errors when relationships are not explicitly defined in the schema cache.
- Updated Gemini AI tracking integration to ensure all calls are recorded correctly.
- Improved error handling in admin dashboard.

src/app/admin/page.tsx

@@ -29,30 +29,38 @@ export default async function AdminPage() {
     // Fetch global API stats
     const stats = await getGlobalApiStats();
 
-    // Fetch recent API usage
+    // Fetch recent API usage without join to avoid relationship errors
     console.log('[Admin Page] Fetching recent API usage...');
-    const { data: recentUsage, error: recentError } = await supabase
+    const { data: recentUsageRaw, error: recentError } = await supabase
         .from('api_usage')
-        .select(`
+        .select('*')
-            *,
-            profiles:user_id (
-                username
-            )
-        `)
         .order('created_at', { ascending: false })
         .limit(50);
 
-    console.log('[Admin Page] Recent usage - count:', recentUsage?.length, 'error:', recentError);
+    console.log('[Admin Page] Recent usage raw - count:', recentUsageRaw?.length, 'error:', recentError);
+
+    // Get unique user IDs from recent usage
+    const recentUserIds = Array.from(new Set(recentUsageRaw?.map(u => u.user_id) || []));
+
+    // Fetch profiles for these users
+    const { data: recentProfiles } = recentUserIds.length > 0
+        ? await supabase.from('profiles').select('id, username').in('id', recentUserIds)
+        : { data: [] };
+
+    // Combine usage with profiles
+    const recentUsage = recentUsageRaw?.map(usage => ({
+        ...usage,
+        profiles: recentProfiles?.find(p => p.id === usage.user_id) || { username: 'Unknown' }
+    })) || [];
 
     // Fetch per-user statistics
-    const { data: userStats } = await supabase
+    const { data: userStatsRaw } = await supabase
         .from('api_usage')
-        .select('user_id, api_type')
+        .select('user_id, api_type');
-        .order('created_at', { ascending: false });
 
     // Group by user
     const userStatsMap = new Map<string, { googleSearch: number; geminiAi: number; total: number }>();
-    userStats?.forEach(item => {
+    userStatsRaw?.forEach(item => {
         const current = userStatsMap.get(item.user_id) || { googleSearch: 0, geminiAi: 0, total: 0 };
         if (item.api_type === 'google_search') current.googleSearch++;
         if (item.api_type === 'gemini_ai') current.geminiAi++;
@@ -66,10 +74,9 @@ export default async function AdminPage() {
         .slice(0, 10)
         .map(([userId]) => userId);
 
-    const { data: topUsers } = await supabase
+    const { data: topUsers } = topUserIds.length > 0
-        .from('profiles')
+        ? await supabase.from('profiles').select('id, username').in('id', topUserIds)
-        .select('id, username')
+        : { data: [] };
-        .in('id', topUserIds);
 
     const topUsersWithStats = topUsers?.map(user => ({
         ...user,