feat: floating tab bar, NLP date parsing, and task date picker

- Tab bar: TickTick-style floating pill (cornerRadius 28, shadow, systemGray5 active highlight)
- NLP: month+day parsing (8th June, June 8), recurrence (every year/week/etc), intent stripping (remind me of)
- Recurrence chip in add-task toolbar; isRecurring saved with task
- Date chip defaults to Today on new tasks; tapping opens full date picker
- Date picker: calendar grid, inline time wheel, Repeat menu (Date tab)
- Duration tab: Start/End column selector, live duration counter, All Day toggle
- TaskItem: added endDate and isAllDay fields
- Fixed hidden Unicode character corrupting + operator in TodayView

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

KisaniCal/Models/TaskItem.swift

@@ -12,6 +12,9 @@ struct TaskItem: Identifiable, Codable, Equatable {
     var category: TaskCategory = .reminder
     var taskColor: TaskColor = .orange
     var isRecurring: Bool = false
+    var isPinned: Bool = false
+    var endDate: Date? = nil
+    var isAllDay: Bool = false
 }
 
 enum Quadrant: String, CaseIterable, Identifiable, Codable {
@@ -84,12 +87,26 @@ class TaskViewModel: ObservableObject {
             .sorted { ($0.dueDate ?? .distantFuture) < ($1.dueDate ?? .distantFuture) }
     }
     var upcomingTasks: [TaskItem] {
-        let tomorrow = Calendar.current.date(byAdding: .day, value: 1,
-                           to: Calendar.current.startOfDay(for: Date()))!
+        let cal = Calendar.current
+        let fourDays = cal.date(byAdding: .day, value: 4, to: cal.startOfDay(for: Date()))!
         return tasks
-            .filter { !$0.isComplete && ($0.dueDate ?? .distantFuture) >= tomorrow }
+            .filter { !$0.isComplete && ($0.dueDate ?? .distantFuture) >= fourDays }
             .sorted { ($0.dueDate ?? .distantFuture) < ($1.dueDate ?? .distantFuture) }
     }
+    var next3DaysTasks: [(date: Date, tasks: [TaskItem])] {
+        let cal = Calendar.current
+        let today = cal.startOfDay(for: Date())
+        return (1...3).compactMap { offset -> (Date, [TaskItem])? in
+            guard let day = cal.date(byAdding: .day, value: offset, to: today),
+                  let nextDay = cal.date(byAdding: .day, value: 1, to: day) else { return nil }
+            let dayTasks = tasks.filter {
+                !$0.isComplete &&
+                ($0.dueDate ?? .distantFuture) >= day &&
+                ($0.dueDate ?? .distantFuture) < nextDay
+            }.sorted { ($0.dueDate ?? .distantFuture) < ($1.dueDate ?? .distantFuture) }
+            return dayTasks.isEmpty ? nil : (day, dayTasks)
+        }
+    }
     var completedTodayTasks: [TaskItem] {
         let startOfDay = Calendar.current.startOfDay(for: Date())
         return tasks
@@ -104,15 +121,42 @@ class TaskViewModel: ObservableObject {
         save()
     }
     func tasks(for quadrant: Quadrant) -> [TaskItem] {
-        tasks.filter { $0.quadrant == quadrant }
+        tasks
+            .filter { $0.quadrant == quadrant }
+            .sorted { $0.isPinned && !$1.isPinned }
+    }
+
+    func pin(_ task: TaskItem) {
+        guard let idx = tasks.firstIndex(where: { $0.id == task.id }) else { return }
+        tasks[idx].isPinned.toggle()
+        save()
+    }
+
+    func setDate(_ task: TaskItem, date: Date?) {
+        guard let idx = tasks.firstIndex(where: { $0.id == task.id }) else { return }
+        tasks[idx].dueDate = date
+        save()
+    }
+
+    func setCategory(_ task: TaskItem, category: TaskCategory) {
+        guard let idx = tasks.firstIndex(where: { $0.id == task.id }) else { return }
+        tasks[idx].category = category
+        save()
+    }
+    func moveToQuadrant(taskID: UUID, quadrant: Quadrant) {
+        guard let idx = tasks.firstIndex(where: { $0.id == taskID }) else { return }
+        tasks[idx].quadrant = quadrant
+        save()
     }
 
     func addTask(title: String, dueDate: Date?, hasTime: Bool = false,
                  quadrant: Quadrant = .urgent, category: TaskCategory = .reminder,
-                 taskColor: TaskColor = .orange, isRecurring: Bool = false) {
+                 taskColor: TaskColor = .orange, isRecurring: Bool = false,
+                 endDate: Date? = nil, isAllDay: Bool = false) {
         tasks.append(TaskItem(title: title, dueDate: dueDate, hasTime: hasTime,
                               quadrant: quadrant, category: category,
-                              taskColor: taskColor, isRecurring: isRecurring))
+                              taskColor: taskColor, isRecurring: isRecurring,
+                              endDate: endDate, isAllDay: isAllDay))
         save()
     }