feat(ui) : add DTOs and services for calendar fields, recurrence, and Zimbra settings

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/services/dto/task.ts

@@ -29,6 +29,23 @@ export type Task = {
         status: string
         title: string
     } | null
+    scheduledStart: string | null
+    scheduledEnd: string | null
+    deadline: string | null
+    syncToCalendar: boolean
+    calendarSyncError: string | null
+    recurrence: {
+        id: number
+        '@id'?: string
+        type: 'daily' | 'weekly' | 'monthly' | 'yearly'
+        interval: number
+        daysOfWeek: string[] | null
+        dayOfMonth: number | null
+        weekOfMonth: number | null
+        endDate: string | null
+        maxOccurrences: number | null
+        occurrenceCount: number
+    } | null
 }
 
 export type TaskWrite = {
@@ -43,4 +60,9 @@ export type TaskWrite = {
     tags: string[]
     archived?: boolean
     clientTicket?: string | null
+    scheduledStart?: string | null
+    scheduledEnd?: string | null
+    deadline?: string | null
+    syncToCalendar?: boolean
+    recurrence?: string | null
 }