feat: Implement app versioning and update gitignore

- Adds appVersion and buildNumber to AppConfig.swift for centralized version management.
- Updates scryfallUserAgent to use the dynamic appVersion.
- Updates .gitignore to exclude AI asset and training directories.
- Adds a version check step to the README release checklist.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

IYmtg_App_iOS/AppConfig.swift

@@ -22,9 +22,13 @@ enum CurrencyCode: String, CaseIterable, Codable {
 struct AppConfig {
     // 1. CONTACT EMAIL (Required by Scryfall)
     static let contactEmail = "support@iymtg.com" // Example: Use your real email
-    
+
     // 2. IN-APP PURCHASE ID (Use a "Consumable" type in App Store Connect for repeatable tips)
     static let tipJarProductIDs: [String] = [] // Example: Use your real Product ID
+
+    // 3. VERSIONING
+    static let appVersion = "1.0.0" // Follows Semantic Versioning (Major.Minor.Patch)
+    static let buildNumber = "1"      // Increments with each build submitted to App Store Connect
     
     // Feature Flags
     static let enableFoilDetection = true
@@ -53,7 +57,7 @@ struct AppConfig {
     }
     
     static var scryfallUserAgent: String {
-        return "IYmtg/1.0 (\(contactEmail))"
+        return "IYmtg/\(appVersion) (\(contactEmail))"
     }
     
     static func validate() {