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/Data/RecipeModels.swift

@@ -28,7 +28,7 @@ struct Recipe: Codable {
 
 
 extension Recipe: Identifiable, Hashable {
-    var id: String { name }
+    var id: Int { recipe_id }
 }
 
 
@@ -93,29 +93,67 @@ struct RecipeDetail: Codable {
     
     // Custom decoder to handle value type ambiguity
     private enum CodingKeys: String, CodingKey {
-        case name, keywords, dateCreated, dateModified, imageUrl, id, prepTime, cookTime, totalTime, description, url, recipeYield, recipeCategory, tool, recipeIngredient, recipeInstructions, nutrition
+        case name, keywords, dateCreated, dateModified, image, imageUrl, id, prepTime, cookTime, totalTime, description, url, recipeYield, recipeCategory, tool, recipeIngredient, recipeInstructions, nutrition
     }
 
     init(from decoder: Decoder) throws {
         let container = try decoder.container(keyedBy: CodingKeys.self)
         name = try container.decode(String.self, forKey: .name)
-        keywords = try container.decode(String.self, forKey: .keywords)
+        keywords = (try? container.decode(String.self, forKey: .keywords)) ?? ""
         dateCreated = try container.decodeIfPresent(String.self, forKey: .dateCreated)
         dateModified = try container.decodeIfPresent(String.self, forKey: .dateModified)
-        imageUrl = try container.decodeIfPresent(String.self, forKey: .imageUrl)
+        // Server import returns "image"; show/index responses and local storage use "imageUrl"
+        imageUrl = (try? container.decodeIfPresent(String.self, forKey: .image))
+            ?? (try? container.decodeIfPresent(String.self, forKey: .imageUrl))
         id = try container.decode(String.self, forKey: .id)
         prepTime = try container.decodeIfPresent(String.self, forKey: .prepTime)
         cookTime = try container.decodeIfPresent(String.self, forKey: .cookTime)
         totalTime = try container.decodeIfPresent(String.self, forKey: .totalTime)
-        description = try container.decode(String.self, forKey: .description)
-        url = try container.decode(String.self, forKey: .url)
-        recipeYield = try container.decode(Int.self, forKey: .recipeYield)
-        recipeCategory = try container.decode(String.self, forKey: .recipeCategory)
-        tool = try container.decode([String].self, forKey: .tool)
-        recipeIngredient = try container.decode([String].self, forKey: .recipeIngredient)
-        recipeInstructions = try container.decode([String].self, forKey: .recipeInstructions)
+        description = (try? container.decode(String.self, forKey: .description)) ?? ""
+        url = try? container.decode(String.self, forKey: .url)
+        recipeCategory = (try? container.decode(String.self, forKey: .recipeCategory)) ?? ""
 
-        nutrition = try container.decode(Dictionary<String, JSONAny>.self, forKey: .nutrition).mapValues { String(describing: $0.value) }
+        // recipeYield: try Int first, then parse leading digits from String
+        if let yieldInt = try? container.decode(Int.self, forKey: .recipeYield) {
+            recipeYield = yieldInt
+        } else if let yieldString = try? container.decode(String.self, forKey: .recipeYield) {
+            let digits = yieldString.prefix(while: { $0.isNumber })
+            recipeYield = Int(digits) ?? 0
+        } else {
+            recipeYield = 0
+        }
+
+        tool = (try? container.decode([String].self, forKey: .tool)) ?? []
+        recipeIngredient = (try? container.decode([String].self, forKey: .recipeIngredient)) ?? []
+        recipeInstructions = (try? container.decode([String].self, forKey: .recipeInstructions)) ?? []
+
+        if let nutritionDict = try? container.decode(Dictionary<String, JSONAny>.self, forKey: .nutrition) {
+            nutrition = nutritionDict.mapValues { String(describing: $0.value) }
+        } else {
+            nutrition = [:]
+        }
+    }
+
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(name, forKey: .name)
+        try container.encode(keywords, forKey: .keywords)
+        try container.encodeIfPresent(dateCreated, forKey: .dateCreated)
+        try container.encodeIfPresent(dateModified, forKey: .dateModified)
+        // Encode under "image" — the key the server expects for create/update
+        try container.encodeIfPresent(imageUrl, forKey: .image)
+        try container.encode(id, forKey: .id)
+        try container.encodeIfPresent(prepTime, forKey: .prepTime)
+        try container.encodeIfPresent(cookTime, forKey: .cookTime)
+        try container.encodeIfPresent(totalTime, forKey: .totalTime)
+        try container.encode(description, forKey: .description)
+        try container.encodeIfPresent(url, forKey: .url)
+        try container.encode(recipeYield, forKey: .recipeYield)
+        try container.encode(recipeCategory, forKey: .recipeCategory)
+        try container.encode(tool, forKey: .tool)
+        try container.encode(recipeIngredient, forKey: .recipeIngredient)
+        try container.encode(recipeInstructions, forKey: .recipeInstructions)
+        try container.encode(nutrition, forKey: .nutrition)
     }
 }