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/EventCardBase.tsx

@@ -75,11 +75,19 @@ export const EventCardBase = ({
           borderBottomColor: theme.borderPrimary,
         }}
       >
-        <Text className="font-bold text-base" style={{ color: theme.textPrimary }}>{title}</Text>
+        <Text
+          className="font-bold text-base"
+          style={{ color: theme.textPrimary }}
+        >
+          {title}
+        </Text>
       </View>
 
       {/* Content */}
-      <View className="px-3 py-2" style={{ backgroundColor: theme.secondaryBg }}>
+      <View
+        className="px-3 py-2"
+        style={{ backgroundColor: theme.secondaryBg }}
+      >
         {/* Date */}
         <View className="flex-row items-center mb-1">
           <Feather
@@ -116,18 +124,13 @@ export const EventCardBase = ({
               color={theme.textPrimary}
               style={{ marginRight: 8 }}
             />
-            <Text style={{ color: theme.textPrimary }}>
-              Wiederkehrend
-            </Text>
+            <Text style={{ color: theme.textPrimary }}>Wiederkehrend</Text>
           </View>
         )}
 
         {/* Description */}
         {description && (
-          <Text
-            style={{ color: theme.textPrimary }}
-            className="text-sm mt-1"
-          >
+          <Text style={{ color: theme.textPrimary }} className="text-sm mt-1">
             {description}
           </Text>
         )}