feat: metrics on Manager page

hooks/use-metrics.ts

@@ -0,0 +1,63 @@
+import { useState, useEffect, useTransition, useCallback } from 'react';
+import { getWeeklyMetrics, getVelocityTrends } from '@/actions/metrics';
+import { WeeklyMetricsOverview, VelocityTrend } from '@/services/metrics';
+
+export function useWeeklyMetrics(date?: Date) {
+  const [metrics, setMetrics] = useState<WeeklyMetricsOverview | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [isPending, startTransition] = useTransition();
+
+  const fetchMetrics = useCallback(() => {
+    startTransition(async () => {
+      setError(null);
+      const result = await getWeeklyMetrics(date);
+      
+      if (result.success && result.data) {
+        setMetrics(result.data);
+      } else {
+        setError(result.error || 'Failed to fetch metrics');
+      }
+    });
+  }, [date, startTransition]);
+
+  useEffect(() => {
+    fetchMetrics();
+  }, [date, fetchMetrics]);
+
+  return { 
+    metrics, 
+    loading: isPending, 
+    error, 
+    refetch: fetchMetrics 
+  };
+}
+
+export function useVelocityTrends(weeksBack: number = 4) {
+  const [trends, setTrends] = useState<VelocityTrend[]>([]);
+  const [error, setError] = useState<string | null>(null);
+  const [isPending, startTransition] = useTransition();
+
+  const fetchTrends = useCallback(() => {
+    startTransition(async () => {
+      setError(null);
+      const result = await getVelocityTrends(weeksBack);
+      
+      if (result.success && result.data) {
+        setTrends(result.data);
+      } else {
+        setError(result.error || 'Failed to fetch velocity trends');
+      }
+    });
+  }, [weeksBack, startTransition]);
+
+  useEffect(() => {
+    fetchTrends();
+  }, [weeksBack, fetchTrends]);
+
+  return { 
+    trends, 
+    loading: isPending, 
+    error, 
+    refetch: fetchTrends 
+  };
+}