Add RRuleDisplay component and clean up unused imports

- Create new RRuleDisplay component for better recurrence rule formatting
- Replace Badge with RRuleDisplay in EventCard for improved UX
- Remove unused imports across multiple files (CalendarEvent, Badge, Card components)
- Remove unused catch parameter in ai-event route

src/components/recurrence-picker.tsx

@@ -5,7 +5,6 @@ import { Input } from "@/components/ui/input"
 import { Label } from "@/components/ui/label"
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select"
 import { Checkbox } from "@/components/ui/checkbox"
-import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
 
 type Recurrence = {
   freq: "NONE" | "DAILY" | "WEEKLY" | "MONTHLY"