feat: add widget extension — small, medium, large

- KisaniCalWidget: 3 sizes sharing the app's design language
  Small: date badge + kisaniCAL. wordmark + task count
  Medium: badge + task list (3 items) + workout row
  Large: badge + full task list (6 items) + workout row

- WidgetDataStore (Shared/): lightweight Codable types for App Group
  UserDefaults cross-process data exchange

- WidgetBridge: TaskViewModel/WorkoutViewModel extensions that sync
  data into App Group and call WidgetCenter.reloadAllTimelines()

- ContentView: calls syncWidget() on appear and scene becoming active

- project.yml + entitlements updated; project regenerated via xcodegen

KisaniCal/ContentView.swift

@@ -73,12 +73,19 @@ struct ContentView: View {
             OnboardingView(isPresented: $showOnboarding)
                 .onDisappear { hasOnboarded = true }
         }
-        .onAppear { if !hasOnboarded { showOnboarding = true } }
+        .onAppear {
+            if !hasOnboarded { showOnboarding = true }
+            taskVM.syncWidget()
+            workoutVM.syncWidget()
+        }
         .onChange(of: scenePhase) { phase in
             if phase == .active {
                 NotificationManager.shared.reschedule(workoutVM: workoutVM, taskVM: taskVM)
+                taskVM.syncWidget()
+                workoutVM.syncWidget()
             }
         }
+        .onChange(of: taskVM.tasks.count) { _ in taskVM.syncWidget() }
         .onChange(of: workoutVM.doneSets) { _ in
             NotificationManager.shared.reschedule(workoutVM: workoutVM, taskVM: taskVM)
         }