Add meal plan feature with cross-device sync and automatic stale data cleanup

Introduces weekly meal planning with a calendar-based tab view, per-recipe
date assignments synced via Nextcloud Cookbook custom metadata, and 30-day
automatic pruning of old entries on load, save, and sync merge.

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

Nextcloud Cookbook iOS Client/Views/Tabs/SearchTabView.swift

@@ -11,6 +11,7 @@ import SwiftUI
 struct SearchTabView: View {
     @EnvironmentObject var viewModel: SearchTabView.ViewModel
     @EnvironmentObject var appState: AppState
+    @EnvironmentObject var mealPlan: MealPlanManager
 
     var body: some View {
         NavigationStack {
@@ -113,6 +114,7 @@ struct SearchTabView: View {
             .navigationTitle(viewModel.searchText.isEmpty ? "Search recipe" : "Search Results")
             .navigationDestination(for: Recipe.self) { recipe in
                 RecipeView(viewModel: RecipeView.ViewModel(recipe: recipe))
+                    .environmentObject(mealPlan)
             }
             .searchable(text: $viewModel.searchText, prompt: "Search recipes/keywords")
             .onSubmit(of: .search) {