feat: add recurring event deletion with three modes

Implement three deletion modes for recurring events:
- single: exclude specific occurrence via EXDATE mechanism
- future: set RRULE UNTIL to stop future occurrences
- all: delete entire event series

Changes include:
- Add exceptionDates field to CalendarEvent model
- Add RecurringDeleteMode type and DeleteRecurringEventDTO
- EventService.deleteRecurring() with mode-based logic using rrule library
- EventController DELETE endpoint accepts mode/occurrenceDate query params
- recurrenceExpander filters out exception dates during expansion
- AI tools support deleteMode and occurrenceDate for proposed deletions
- ChatService.confirmEvent() handles recurring delete modes
- New DeleteEventModal component for unified delete confirmation UI
- Calendar screen integrates modal for both recurring and non-recurring events

apps/client/src/components/BaseButton.tsx

@@ -8,7 +8,7 @@ type BaseButtonProps = {
   solid?: boolean;
 };
 
-const BaseButton = ({children, onPress, solid = false}: BaseButtonProps) => {
+const BaseButton = ({ children, onPress, solid = false }: BaseButtonProps) => {
   const { theme } = useThemeStore();
   return (
     <Pressable
@@ -16,9 +16,7 @@ const BaseButton = ({children, onPress, solid = false}: BaseButtonProps) => {
       onPress={onPress}
       style={{
         borderColor: theme.borderPrimary,
-        backgroundColor: solid
-          ? theme.chatBot
-          : theme.primeBg,
+        backgroundColor: solid ? theme.chatBot : theme.primeBg,
         shadowColor: theme.shadowColor,
         shadowOffset: { width: 0, height: 2 },
         shadowOpacity: 0.25,