feat: Add multi-family support with family selector UI

- Created useSelectedFamily hook for managing family selection across app
- Added family selector dropdown to family page when user has multiple families
- Family selection persists in localStorage
- Fixed bug where users could only see their first family
- Updated dev port from 3005 to 3030 in package.json

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

maternal-web/hooks/useSelectedFamily.ts

@@ -0,0 +1,47 @@
+import { useState, useEffect } from 'react';
+import { useAuth } from '@/lib/auth/AuthContext';
+
+const SELECTED_FAMILY_KEY = 'selectedFamilyIndex';
+
+/**
+ * Hook to manage selected family across the app
+ * Stores selection in localStorage for persistence
+ */
+export function useSelectedFamily() {
+  const { user } = useAuth();
+  const userFamilies = user?.families || [];
+
+  // Initialize from localStorage or default to 0
+  const [selectedIndex, setSelectedIndex] = useState<number>(() => {
+    if (typeof window === 'undefined') return 0;
+    const stored = localStorage.getItem(SELECTED_FAMILY_KEY);
+    return stored ? parseInt(stored, 10) : 0;
+  });
+
+  // Ensure selectedIndex is within bounds
+  useEffect(() => {
+    if (selectedIndex >= userFamilies.length && userFamilies.length > 0) {
+      setSelectedIndex(0);
+    }
+  }, [userFamilies.length, selectedIndex]);
+
+  // Save to localStorage when changed
+  const setSelectedFamily = (index: number) => {
+    setSelectedIndex(index);
+    if (typeof window !== 'undefined') {
+      localStorage.setItem(SELECTED_FAMILY_KEY, index.toString());
+    }
+  };
+
+  const familyId = userFamilies[selectedIndex]?.familyId || null;
+  const familyRole = userFamilies[selectedIndex]?.role || null;
+
+  return {
+    familyId,
+    familyRole,
+    selectedIndex,
+    setSelectedIndex: setSelectedFamily,
+    userFamilies,
+    hasMultipleFamilies: userFamilies.length > 1,
+  };
+}