Perf: Add final to classes that are not inherited (#574)

bitchatTests/BLEServiceTests.swift

@@ -270,7 +270,7 @@ final class BLEServiceTests: XCTestCase {
 
 // MARK: - Mock Delegate Helper
 
-private class MockBitchatDelegate: BitchatDelegate {
+private final class MockBitchatDelegate: BitchatDelegate {
     private let messageHandler: (BitchatMessage) -> Void
     
     init(_ handler: @escaping (BitchatMessage) -> Void) {

bitchatTests/Mocks/MockBLEService.swift

@@ -26,7 +26,7 @@ import CoreBluetooth
 /// - `autoFloodEnabled` is disabled by default; Integration tests enable it in `setUp()` to
 ///   simulate broadcast propagation across the mesh. E2E tests keep it off and perform explicit
 ///   relays when needed.
-class MockBLEService: NSObject {
+final class MockBLEService: NSObject {
     // Enable automatic flooding for public messages in integration tests only
     static var autoFloodEnabled: Bool = false
     

bitchatTests/TestUtilities/TestHelpers.swift

@@ -10,7 +10,7 @@ import Foundation
 import CryptoKit
 @testable import bitchat
 
-class TestHelpers {
+final class TestHelpers {
     
     // MARK: - Key Generation