Add category and recipe sorting with multiple modes and order inversion

Categories on the main page can be sorted by Recently Used, Alphabetical,
or Manual (drag-to-reorder). The sort menu appears inline next to the
Categories header. All Recipes is included in the sort order and manual
reorder sheet. Recipes within category and all-recipes lists can be sorted
by Recently Added or Alphabetical, with the sort button in the toolbar.
All non-manual sort modes support order inversion via a Reverse/Default
Order toggle. Date parsing handles both formatted strings and Unix
timestamps, with recipe_id as fallback when dates are unavailable.

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

Nextcloud Cookbook iOS Client/Views/MainView.swift

@@ -79,6 +79,10 @@ struct MainView: View {
             // Load recently viewed recipes
             await appState.loadRecentRecipes()
 
+            // Load category sorting data
+            await appState.loadCategoryAccessDates()
+            await appState.loadManualCategoryOrder()
+
             // Open detail view for default category
             if UserSettings.shared.defaultCategory != "" {
                 if let cat = appState.categories.first(where: { c in