Add unified task menu, Live Activity, and calendar event actions

Task context menu (new shared TaskMenuItems) consistent across Today,
Matrix, and Calendar: Pin · Date · Move · Priority · Tags · Add to Live
Activity · Delete. Adds TaskViewModel.setPriority.

Live Activity (ActivityKit):
- TaskActivityAttributes shared between app and widget targets
- LiveActivityManager (start/update/end/toggle, iOS 16.1+)
- TaskLiveActivity widget: lock-screen banner + Dynamic Island
- NSSupportsLiveActivities via project.yml; project regenerated

Calendar events (non-subscription, writable only):
- Edit via system EKEventEditViewController (EventEditView wrapper)
- Delete via new CalendarStore.deleteEvent

Also sweeps in prior in-progress edits already present in the working
tree (AuthManager, NotificationManager, TaskItem, task views) and the
updated ISSUES.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

KisaniCalWidgets/KisaniCalWidgets.swift

@@ -111,5 +111,6 @@ struct KisaniWidgetBundle: WidgetBundle {
         TasksCompleteWidget()
         LockScreenWidget()
         LockScreenCircularWidget()
+        TaskLiveActivity()
     }
 }