Add Apple Reminders integration for grocery list with local mapping persistence

Introduce a GroceryListManager facade that delegates to either the existing
in-app GroceryList or a new RemindersGroceryStore backed by EventKit. Users
choose the mode in Settings; when Reminders mode is active the Grocery List
tab is hidden. Recipe-to-reminder grouping uses a local mapping file
(reminder_mappings.data) instead of polluting the reminder's notes field,
with automatic pruning when reminders are deleted externally.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Nextcloud Cookbook iOS Client/Data/GroceryListManager.swift

@@ -0,0 +1,144 @@
+//
+//  GroceryListManager.swift
+//  Nextcloud Cookbook iOS Client
+//
+
+import EventKit
+import Foundation
+import OSLog
+import SwiftUI
+
+@MainActor
+class GroceryListManager: ObservableObject {
+    @Published var groceryDict: [String: GroceryRecipe] = [:]
+
+    let localStore = GroceryList()
+    let remindersStore = RemindersGroceryStore()
+
+    private var mode: GroceryListMode {
+        GroceryListMode(rawValue: UserSettings.shared.groceryListMode) ?? .inApp
+    }
+
+    init() {
+        remindersStore.onDataChanged = { [weak self] in
+            guard let self else { return }
+            if self.mode == .appleReminders {
+                self.groceryDict = self.remindersStore.groceryDict
+            }
+        }
+    }
+
+    // MARK: - Grocery Operations
+
+    func addItem(_ itemName: String, toRecipe recipeId: String, recipeName: String? = nil) {
+        switch mode {
+        case .inApp:
+            localStore.addItem(itemName, toRecipe: recipeId, recipeName: recipeName)
+            groceryDict = localStore.groceryDict
+        case .appleReminders:
+            remindersStore.addItem(itemName, toRecipe: recipeId, recipeName: recipeName)
+            groceryDict = remindersStore.groceryDict
+        }
+    }
+
+    func addItems(_ items: [String], toRecipe recipeId: String, recipeName: String? = nil) {
+        switch mode {
+        case .inApp:
+            localStore.addItems(items, toRecipe: recipeId, recipeName: recipeName)
+            groceryDict = localStore.groceryDict
+        case .appleReminders:
+            remindersStore.addItems(items, toRecipe: recipeId, recipeName: recipeName)
+            groceryDict = remindersStore.groceryDict
+        }
+    }
+
+    func deleteItem(_ itemName: String, fromRecipe recipeId: String) {
+        switch mode {
+        case .inApp:
+            localStore.deleteItem(itemName, fromRecipe: recipeId)
+            groceryDict = localStore.groceryDict
+        case .appleReminders:
+            remindersStore.deleteItem(itemName, fromRecipe: recipeId)
+            // Cache update happens async in RemindersGroceryStore via onDataChanged
+        }
+    }
+
+    func deleteGroceryRecipe(_ recipeId: String) {
+        switch mode {
+        case .inApp:
+            localStore.deleteGroceryRecipe(recipeId)
+            groceryDict = localStore.groceryDict
+        case .appleReminders:
+            remindersStore.deleteGroceryRecipe(recipeId)
+        }
+    }
+
+    func deleteAll() {
+        switch mode {
+        case .inApp:
+            localStore.deleteAll()
+            groceryDict = localStore.groceryDict
+        case .appleReminders:
+            remindersStore.deleteAll()
+        }
+    }
+
+    func toggleItemChecked(_ groceryItem: GroceryRecipeItem) {
+        switch mode {
+        case .inApp:
+            localStore.toggleItemChecked(groceryItem)
+        case .appleReminders:
+            // Reminders don't support checked state in our model
+            break
+        }
+    }
+
+    func containsItem(at recipeId: String, item: String) -> Bool {
+        switch mode {
+        case .inApp:
+            return localStore.containsItem(at: recipeId, item: item)
+        case .appleReminders:
+            return remindersStore.containsItem(at: recipeId, item: item)
+        }
+    }
+
+    func containsRecipe(_ recipeId: String) -> Bool {
+        switch mode {
+        case .inApp:
+            return localStore.containsRecipe(recipeId)
+        case .appleReminders:
+            return remindersStore.containsRecipe(recipeId)
+        }
+    }
+
+    func load() async {
+        switch mode {
+        case .inApp:
+            await localStore.load()
+            groceryDict = localStore.groceryDict
+        case .appleReminders:
+            await remindersStore.load()
+            groceryDict = remindersStore.groceryDict
+        }
+    }
+
+    func save() {
+        if mode == .inApp {
+            localStore.save()
+        }
+    }
+
+    // MARK: - Reminders Helpers (for Settings UI)
+
+    var remindersPermissionStatus: EKAuthorizationStatus {
+        remindersStore.checkPermissionStatus()
+    }
+
+    func requestRemindersAccess() async -> Bool {
+        await remindersStore.requestAccess()
+    }
+
+    func availableReminderLists() -> [EKCalendar] {
+        remindersStore.availableReminderLists()
+    }
+}