Modernize networking layer and fix category navigation and recipe list bugs

Network layer:
- Replace static CookbookApi protocol with instance-based CookbookApiProtocol
  using async/throws instead of tuple returns
- Refactor ApiRequest to use URLComponents for proper URL encoding, replace
  print statements with OSLog, and return typed NetworkError cases
- Add structured NetworkError variants (httpError, connectionError, etc.)
- Remove global cookbookApi constant in favor of injected dependency on AppState
- Delete unused RecipeEditViewModel, RecipeScraper, and Scraper playground

Data & model fixes:
- Add custom Decodable for RecipeDetail with safe fallbacks for malformed JSON
- Make Category Hashable/Equatable use only `name` so NavigationSplitView
  selection survives category refreshes with updated recipe_count
- Return server-assigned ID from uploadRecipe so new recipes get their ID
  before the post-upload refresh block executes

View updates:
- Refresh both old and new category recipe lists after upload when category
  changes, mapping empty recipeCategory to "*" for uncategorized recipes
- Raise deployment target to iOS 18, adopt new SwiftUI API conventions
- Clean up alerts, onboarding views, and settings

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

Nextcloud Cookbook iOS Client.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -1,14 +1,6 @@
 {
+  "originHash" : "314ca0b5cf5f134470eb4e9e12133500ae78d8b9a08f490e0065f2b3ceb4a25a",
   "pins" : [
-    {
-      "identity" : "swiftsoup",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/scinfu/SwiftSoup.git",
-      "state" : {
-        "revision" : "8b6cf29eead8841a1fa7822481cb3af4ddaadba6",
-        "version" : "2.6.1"
-      }
-    },
     {
       "identity" : "tppdf",
       "kind" : "remoteSourceControl",
@@ -19,5 +11,5 @@
       }
     }
   ],
-  "version" : 2
+  "version" : 3
 }