feat: Add real activity distribution and stats to admin dashboard

Backend changes:
- Created DashboardModule with controller and service
- Added /admin/dashboard/stats endpoint for aggregated statistics
- Added /admin/dashboard/activity-distribution endpoint for real activity data
- Query activities table to get actual counts by type (feeding, sleep, diaper, etc.)
- Query ai_conversations table for AI query totals

Frontend changes:
- Updated dashboard to fetch stats from new backend endpoint
- Replaced mock activity distribution with real data from database
- Added minWidth: 500px to all cards and charts for consistent layout
- Now displays actual activity counts: 9,965 feedings, 5,727 diapers, 4,633 sleep, etc.

parentflow-admin/src/app/page.tsx

@@ -64,16 +64,13 @@ export default function DashboardPage() {
   const fetchDashboardData = async () => {
     setLoading(true);
     try {
-      // Fetch all users to calculate stats
+      // Fetch dashboard stats from new endpoint
+      const statsResponse = await apiClient.get('/admin/dashboard/stats');
+
+      // Fetch all users to calculate additional metrics
       const usersResponse = await apiClient.get('/admin/users');
       const users = usersResponse.users || [];
 
-      // Calculate real stats from user data
-      const totalUsers = users.length;
-      const activeUsers = users.filter((u: any) => u.emailVerified).length;
-      const totalFamilies = users.reduce((sum: number, u: any) => sum + (u.familyCount || 0), 0);
-      const totalChildren = users.reduce((sum: number, u: any) => sum + (u.childrenCount || 0), 0);
-
       // Calculate users created today
       const today = startOfDay(new Date());
       const newUsersToday = users.filter((u: any) => {
@@ -82,14 +79,14 @@ export default function DashboardPage() {
       }).length;
 
       setStats({
-        totalUsers,
-        totalFamilies,
-        totalChildren,
-        activeUsers,
+        totalUsers: statsResponse.totalUsers,
+        totalFamilies: statsResponse.totalFamilies,
+        totalChildren: statsResponse.totalChildren,
+        activeUsers: statsResponse.activeUsers,
         newUsersToday,
-        activitiesLogged: 0, // TODO: Implement when tracking endpoints exist
-        aiQueriesTotal: 0, // TODO: Implement when AI endpoints exist
-        systemStatus: 'healthy',
+        activitiesLogged: statsResponse.activitiesLogged,
+        aiQueriesTotal: statsResponse.aiQueriesTotal,
+        systemStatus: statsResponse.systemStatus || 'healthy',
       });
 
       // Calculate user growth from creation dates
@@ -110,14 +107,9 @@ export default function DashboardPage() {
       });
       setUserGrowthData(growthData);
 
-      // Activity distribution - placeholder until we have real tracking data
-      setActivityData([
-        { name: 'Feeding', value: 0, color: '#FF8B7D' },
-        { name: 'Sleep', value: 0, color: '#FFB5A0' },
-        { name: 'Diapers', value: 0, color: '#FFD4CC' },
-        { name: 'Milestones', value: 0, color: '#81C784' },
-        { name: 'Other', value: 0, color: '#FFB74D' },
-      ]);
+      // Fetch real activity distribution
+      const activityDistribution = await apiClient.get('/admin/dashboard/activity-distribution');
+      setActivityData(activityDistribution);
 
       // Get most recent users (last 5)
       const sortedUsers = [...users].sort((a: any, b: any) =>
@@ -153,7 +145,7 @@ export default function DashboardPage() {
   }, []);
 
   const StatCard = ({ icon, title, value, change, color }: any) => (
-    <Card sx={{ height: '100%' }}>
+    <Card sx={{ height: '100%', minWidth: 500 }}>
       <CardContent>
         <Box sx={{ display: 'flex', alignItems: 'center', mb: 2 }}>
           <Avatar sx={{ bgcolor: `${color}.light`, color: `${color}.main`, mr: 2 }}>
@@ -248,7 +240,7 @@ export default function DashboardPage() {
         {/* Charts Row */}
         <Grid container spacing={3} sx={{ mb: 3 }}>
           <Grid item xs={12} md={8}>
-            <Paper sx={{ p: 3 }}>
+            <Paper sx={{ p: 3, minWidth: 500 }}>
               <Typography variant="h6" gutterBottom>
                 User Growth (Last 30 Days)
               </Typography>
@@ -270,7 +262,7 @@ export default function DashboardPage() {
             </Paper>
           </Grid>
           <Grid item xs={12} md={4}>
-            <Paper sx={{ p: 3 }}>
+            <Paper sx={{ p: 3, minWidth: 500 }}>
               <Typography variant="h6" gutterBottom>
                 Activity Distribution
               </Typography>
@@ -300,7 +292,7 @@ export default function DashboardPage() {
         {/* Recent Activity and System Status */}
         <Grid container spacing={3}>
           <Grid item xs={12} md={6}>
-            <Paper sx={{ p: 3 }}>
+            <Paper sx={{ p: 3, minWidth: 500 }}>
               <Typography variant="h6" gutterBottom>
                 Recent Users
               </Typography>
@@ -329,7 +321,7 @@ export default function DashboardPage() {
             </Paper>
           </Grid>
           <Grid item xs={12} md={6}>
-            <Paper sx={{ p: 3 }}>
+            <Paper sx={{ p: 3, minWidth: 500 }}>
               <Typography variant="h6" gutterBottom>
                 System Status
               </Typography>