Implement bank transfer app flows

Thijooree iOS/Storage/ContactsCache.swift

@@ -0,0 +1,25 @@
+import Foundation
+
+// Encrypted contacts cache backed by UserDefaults (same pattern as AccountCache).
+struct ContactsCache {
+    static let shared = ContactsCache()
+    private let udKey = "thijooree_contacts_v1"
+    private init() {}
+
+    func save(_ contacts: [BankContact]) {
+        guard let json = try? JSONEncoder().encode(contacts),
+              let encrypted = try? CacheEncryption.shared.encryptData(json) else { return }
+        UserDefaults.standard.set(encrypted, forKey: udKey)
+    }
+
+    func load() -> [BankContact] {
+        guard let encrypted = UserDefaults.standard.string(forKey: udKey),
+              let json = try? CacheEncryption.shared.decryptData(encrypted),
+              let contacts = try? JSONDecoder().decode([BankContact].self, from: json) else { return [] }
+        return contacts
+    }
+
+    func clear() {
+        UserDefaults.standard.removeObject(forKey: udKey)
+    }
+}