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/Network/ApiRequest.swift

@@ -14,7 +14,7 @@ struct ApiRequest {
     let authString: String?
     let headerFields: [HeaderField]
     let body: Data?
-            
+
     init(
         path: String,
         method: RequestMethod,
@@ -28,21 +28,21 @@ struct ApiRequest {
         self.authString = authString
         self.body = body
     }
-    
+
     func send(pathCompletion: Bool = true) async -> (Data?, NetworkError?) {
         Logger.network.debug("\(method.rawValue) \(path) sending ...")
-        
+
         // Prepare URL
         let urlString = pathCompletion ? UserSettings.shared.serverProtocol + UserSettings.shared.serverAddress + path : path
-        print("Full path: \(urlString)")
-        //Logger.network.debug("Full path: \(urlString)")
-        guard let urlStringSanitized = urlString.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) else { return (nil, .unknownError) }
-        guard let url = URL(string: urlStringSanitized) else { return (nil, .unknownError) }
-        
+        guard var components = URLComponents(string: urlString) else { return (nil, .missingUrl) }
+        // Ensure path percent encoding is applied correctly
+        components.percentEncodedPath = components.path.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? components.path
+        guard let url = components.url else { return (nil, .missingUrl) }
+
         // Create URL request
         var request = URLRequest(url: url)
         request.httpMethod = method.rawValue
-        
+
         // Set authentication string, if needed
         if let authString = authString {
             request.setValue(
@@ -50,7 +50,7 @@ struct ApiRequest {
                 forHTTPHeaderField: "Authorization"
             )
         }
-        
+
         // Set other header fields
         for headerField in headerFields {
             request.setValue(
@@ -58,46 +58,38 @@ struct ApiRequest {
                 forHTTPHeaderField: headerField.getField()
             )
         }
-        
+
         // Set http body
         if let body = body {
             request.httpBody = body
         }
-                
+
         // Wait for and return data and (decoded) response
-        var data: Data? = nil
-        var response: URLResponse? = nil
         do {
-            (data, response) = try await URLSession.shared.data(for: request)
-            Logger.network.debug("\(method.rawValue) \(path) SUCCESS!")
-            if let error = decodeURLResponse(response: response as? HTTPURLResponse) {
-                print("\(method.rawValue) \(path) FAILURE: \(error.localizedDescription)")
+            let (data, response) = try await URLSession.shared.data(for: request)
+            if let error = decodeURLResponse(response: response as? HTTPURLResponse, data: data) {
+                Logger.network.debug("\(method.rawValue) \(path) FAILURE: \(error.localizedDescription)")
                 return (nil, error)
             }
-            if let data = data {
-                print(data, String(data: data, encoding: .utf8) as Any)
-                return (data, nil)
-            }
-            return (nil, .unknownError)
+            Logger.network.debug("\(method.rawValue) \(path) SUCCESS!")
+            return (data, nil)
         } catch {
-            let error = decodeURLResponse(response: response as? HTTPURLResponse)
-            Logger.network.debug("\(method.rawValue) \(path) FAILURE: \(error.debugDescription)")
-            return (nil, error)
+            Logger.network.debug("\(method.rawValue) \(path) FAILURE: \(error.localizedDescription)")
+            return (nil, .connectionError(underlying: error))
         }
     }
-    
-    private func decodeURLResponse(response: HTTPURLResponse?) -> NetworkError? {
+
+    private func decodeURLResponse(response: HTTPURLResponse?, data: Data?) -> NetworkError? {
         guard let response = response else {
-            return NetworkError.unknownError
+            return .unknownError(detail: "No HTTP response")
         }
-        print("Status code: ", response.statusCode)
-        switch response.statusCode {
-            case 200...299: return (nil)
-            case 300...399: return (NetworkError.redirectionError)
-            case 400...499: return (NetworkError.clientError)
-            case 500...599: return (NetworkError.serverError)
-            case 600: return (NetworkError.invalidRequest)
-            default: return (NetworkError.unknownError)
+        let statusCode = response.statusCode
+        switch statusCode {
+        case 200...299:
+            return nil
+        default:
+            let body = data.flatMap { String(data: $0, encoding: .utf8) }
+            return .httpError(statusCode: statusCode, body: body)
         }
     }
 }