feat: calendar settings, matrix drill-down, FAB fix, in-app add calendar

- Calendar: redesign connect sheet with Local Calendars grouped view (Default/Other/Subscribed), per-calendar Show/Hide toggle, master enabled toggle, Do Not Disturb toggle; Add Calendar now in-app with Google/Outlook/iCloud/CalDAV/Exchange/Holidays/URL flows instead of opening iOS Calendar app
- Calendar: fix toggle icon (calendar.day.timeline.left / list.bullet.below.rectangle), maintain full month view when switching to task list mode
- Matrix: quadrant header tap drills into detail view (Overdue/Later/Completed sections), task tap opens edit sheet; fix navigationDestination iOS 16 compat
- Tasks: functional reminder picker in date sheet with inline time wheel; birthday NLP detection sets yearly recurrence; dynamic repeat option labels; quadrant badge picker replaces priority flags
- Notifications: fix actor isolation crash in mark-complete handler; per-task reminder scheduling uses reminderDate field; evening check-in notification
- FAB: fix + button hidden behind custom tab bar in TodayView, CalendarView, MatrixView — move background out of ZStack children into .background() modifier
- TaskItem: add reminderDate, recurrenceLabel, endDate, isAllDay fields; Quadrant adds roman/matrixLabel/color/softColor; TaskViewModel adds updateTask/pin/setDate/setCategory

Co-Authored-By: Kutesir <tqwyy79vzn@privaterelay.appleid.com>

KisaniCal/Models/TaskItem.swift

@@ -12,10 +12,12 @@ struct TaskItem: Identifiable, Codable, Equatable {
     var category: TaskCategory = .reminder
     var taskColor: TaskColor = .orange
     var isRecurring: Bool = false
+    var recurrenceLabel: String? = nil
     var isPinned: Bool = false
     var endDate: Date? = nil
     var isAllDay: Bool = false
     var priority: Priority = .none
+    var reminderDate: Date? = nil
 }
 
 enum Priority: String, Codable, CaseIterable, Identifiable {
@@ -50,6 +52,42 @@ enum Quadrant: String, CaseIterable, Identifiable, Codable {
     case schedule  = "Schedule It"
     case delegate_ = "Delegate"
     case eliminate = "Eliminate"
+
+    var roman: String {
+        switch self {
+        case .urgent:    return "I"
+        case .schedule:  return "II"
+        case .delegate_: return "III"
+        case .eliminate: return "IV"
+        }
+    }
+
+    var matrixLabel: String {
+        switch self {
+        case .urgent:    return "Urgent & Important"
+        case .schedule:  return "Not Urgent & Important"
+        case .delegate_: return "Urgent & Unimportant"
+        case .eliminate: return "Not Urgent & Unimportant"
+        }
+    }
+
+    var color: Color {
+        switch self {
+        case .urgent:    return AppColors.accent
+        case .schedule:  return AppColors.yellow
+        case .delegate_: return AppColors.blue
+        case .eliminate: return AppColors.green
+        }
+    }
+
+    var softColor: Color {
+        switch self {
+        case .urgent:    return AppColors.accentSoft
+        case .schedule:  return AppColors.yellowSoft
+        case .delegate_: return AppColors.blueSoft
+        case .eliminate: return AppColors.greenSoft
+        }
+    }
 }
 
 enum TaskCategory: String, Codable {
@@ -189,13 +227,30 @@ class TaskViewModel: ObservableObject {
     func addTask(title: String, dueDate: Date?, hasTime: Bool = false,
                  quadrant: Quadrant = .urgent, category: TaskCategory = .reminder,
                  taskColor: TaskColor = .orange, isRecurring: Bool = false,
+                 recurrenceLabel: String? = nil,
                  endDate: Date? = nil, isAllDay: Bool = false,
-                 priority: Priority = .none) {
+                 priority: Priority = .none, reminderDate: Date? = nil) {
         tasks.append(TaskItem(title: title, dueDate: dueDate, hasTime: hasTime,
                               quadrant: quadrant, category: category,
                               taskColor: taskColor, isRecurring: isRecurring,
+                              recurrenceLabel: recurrenceLabel,
                               endDate: endDate, isAllDay: isAllDay,
-                              priority: priority))
+                              priority: priority, reminderDate: reminderDate))
+        save()
+    }
+
+    func updateTask(_ task: TaskItem, title: String, dueDate: Date?, hasTime: Bool,
+                    isRecurring: Bool, recurrenceLabel: String?,
+                    endDate: Date?, isAllDay: Bool, reminderDate: Date?) {
+        guard let idx = tasks.firstIndex(where: { $0.id == task.id }) else { return }
+        tasks[idx].title           = title
+        tasks[idx].dueDate         = dueDate
+        tasks[idx].hasTime         = hasTime
+        tasks[idx].isRecurring     = isRecurring
+        tasks[idx].recurrenceLabel = recurrenceLabel
+        tasks[idx].endDate         = endDate
+        tasks[idx].isAllDay        = isAllDay
+        tasks[idx].reminderDate    = reminderDate
         save()
     }