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

BRING_THE_NOISE.md

@@ -37,7 +37,7 @@ This three-message pattern provides:
 #### NoiseEncryptionService
 The main service managing all Noise operations:
 ```swift
-class NoiseEncryptionService {
+final class NoiseEncryptionService {
     private let staticIdentityKey: Curve25519.KeyAgreement.PrivateKey
     private let sessionManager: NoiseSessionManager
     private let channelEncryption = NoiseChannelEncryption()
@@ -47,7 +47,7 @@ class NoiseEncryptionService {
 #### NoiseSession
 Individual session state for each peer:
 ```swift
-class NoiseSession {
+final class NoiseSession {
     private var handshakeState: NoiseHandshakeState?
     private var sendCipher: NoiseCipherState?
     private var receiveCipher: NoiseCipherState?
@@ -58,7 +58,7 @@ class NoiseSession {
 #### NoiseSessionManager
 Thread-safe session management:
 ```swift
-class NoiseSessionManager {
+final class NoiseSessionManager {
     private var sessions: [String: NoiseSession] = [:]
     private let sessionsQueue = DispatchQueue(label: "noise.sessions", attributes: .concurrent)
 }

bitchat/BitchatApp.swift

@@ -163,7 +163,7 @@ struct BitchatApp: App {
 }
 
 #if os(iOS)
-class AppDelegate: NSObject, UIApplicationDelegate {
+final class AppDelegate: NSObject, UIApplicationDelegate {
     weak var chatViewModel: ChatViewModel?
     
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
@@ -175,7 +175,7 @@ class AppDelegate: NSObject, UIApplicationDelegate {
 #if os(macOS)
 import AppKit
 
-class MacAppDelegate: NSObject, NSApplicationDelegate {
+final class MacAppDelegate: NSObject, NSApplicationDelegate {
     weak var chatViewModel: ChatViewModel?
     
     func applicationWillTerminate(_ notification: Notification) {
@@ -188,7 +188,7 @@ class MacAppDelegate: NSObject, NSApplicationDelegate {
 }
 #endif
 
-class NotificationDelegate: NSObject, UNUserNotificationCenterDelegate {
+final class NotificationDelegate: NSObject, UNUserNotificationCenterDelegate {
     static let shared = NotificationDelegate()
     weak var chatViewModel: ChatViewModel?
     

bitchat/Identity/SecureIdentityStateManager.swift

@@ -96,7 +96,7 @@ import CryptoKit
 /// Singleton manager for secure identity state persistence and retrieval.
 /// Provides thread-safe access to identity mappings with encryption at rest.
 /// All identity data is stored encrypted in the device Keychain for security.
-class SecureIdentityStateManager {
+final class SecureIdentityStateManager {
     static let shared = SecureIdentityStateManager()
     
     private let keychain = KeychainManager.shared

bitchat/Noise/NoiseHandshakeCoordinator.swift

@@ -9,7 +9,7 @@
 import Foundation
 
 /// Coordinates Noise handshakes to prevent race conditions and ensure reliable encryption establishment
-class NoiseHandshakeCoordinator {
+final class NoiseHandshakeCoordinator {
     
     // MARK: - Handshake State
     

bitchat/Noise/NoiseProtocol.swift

@@ -127,7 +127,7 @@ struct NoiseProtocolName {
 /// Handles ChaCha20-Poly1305 AEAD encryption with automatic nonce management
 /// and replay protection using a sliding window algorithm.
 /// - Warning: Nonce reuse would be catastrophic for security
-class NoiseCipherState {
+final class NoiseCipherState {
     // Constants for replay protection
     private static let NONCE_SIZE_BYTES = 4
     private static let REPLAY_WINDOW_SIZE = 1024
@@ -384,7 +384,7 @@ class NoiseCipherState {
 /// Responsible for key derivation, protocol name hashing, and maintaining
 /// the chaining key that provides key separation between handshake messages.
 /// - Note: This class implements the SymmetricState object from the Noise spec
-class NoiseSymmetricState {
+final class NoiseSymmetricState {
     private var cipherState: NoiseCipherState
     private var chainingKey: Data
     private var hash: Data
@@ -488,7 +488,7 @@ class NoiseSymmetricState {
 /// This is the main interface for establishing encrypted sessions between peers.
 /// Manages the handshake state machine, message patterns, and key derivation.
 /// - Important: Each handshake instance should only be used once
-class NoiseHandshakeState {
+final class NoiseHandshakeState {
     private let role: NoiseRole
     private let pattern: NoisePattern
     private var symmetricState: NoiseSymmetricState

bitchat/Noise/NoiseSecurityConsiderations.swift

@@ -61,7 +61,7 @@ struct NoiseSecurityValidator {
 
 // MARK: - Enhanced Noise Session with Security
 
-class SecureNoiseSession: NoiseSession {
+final class SecureNoiseSession: NoiseSession {
     private(set) var messageCount: UInt64 = 0
     private let sessionStartTime = Date()
     private(set) var lastActivityTime = Date()
@@ -135,7 +135,7 @@ class SecureNoiseSession: NoiseSession {
 
 // MARK: - Rate Limiter
 
-class NoiseRateLimiter {
+final class NoiseRateLimiter {
     private var handshakeTimestamps: [String: [Date]] = [:] // peerID -> timestamps
     private var messageTimestamps: [String: [Date]] = [:] // peerID -> timestamps
     

bitchat/Noise/NoiseSession.swift

@@ -250,7 +250,7 @@ class NoiseSession {
 
 // MARK: - Session Manager
 
-class NoiseSessionManager {
+final class NoiseSessionManager {
     private var sessions: [String: NoiseSession] = [:]
     private let localStaticKey: Curve25519.KeyAgreement.PrivateKey
     private let managerQueue = DispatchQueue(label: "chat.bitchat.noise.manager", attributes: .concurrent)

bitchat/Nostr/NostrRelayManager.swift

@@ -4,7 +4,7 @@ import Combine
 
 /// Manages WebSocket connections to Nostr relays
 @MainActor
-class NostrRelayManager: ObservableObject {
+final class NostrRelayManager: ObservableObject {
     static let shared = NostrRelayManager()
     // Track gift-wraps (kind 1059) we initiated so we can log OK acks at info
     private(set) static var pendingGiftWrapIDs = Set<String>()

bitchat/Protocols/BitchatProtocol.swift

@@ -397,7 +397,7 @@ enum DeliveryStatus: Codable, Equatable {
 /// Handles both broadcast messages and private encrypted messages,
 /// with support for mentions, replies, and delivery tracking.
 /// - Note: This is the primary data model for chat messages
-class BitchatMessage: Codable {
+final class BitchatMessage: Codable {
     let id: String
     let sender: String
     let content: String

bitchat/Services/AutocompleteService.swift

@@ -9,7 +9,7 @@
 import Foundation
 
 /// Manages autocomplete functionality for chat
-class AutocompleteService {
+final class AutocompleteService {
     private let mentionRegex = try? NSRegularExpression(pattern: "@([\\p{L}0-9_]*)$", options: [])
     private let commandRegex = try? NSRegularExpression(pattern: "^/([a-z]*)$", options: [])
     

bitchat/Services/CommandProcessor.swift

@@ -17,7 +17,7 @@ enum CommandResult {
 
 /// Processes chat commands in a focused, efficient way
 @MainActor
-class CommandProcessor {
+final class CommandProcessor {
     weak var chatViewModel: ChatViewModel?
     weak var meshService: Transport?
     

bitchat/Services/FavoritesPersistenceService.swift

@@ -3,7 +3,7 @@ import Combine
 
 /// Manages persistent favorite relationships between peers
 @MainActor
-class FavoritesPersistenceService: ObservableObject {
+final class FavoritesPersistenceService: ObservableObject {
     
     struct FavoriteRelationship: Codable {
         let peerNoisePublicKey: Data

bitchat/Services/KeychainManager.swift

@@ -10,7 +10,7 @@ import Foundation
 import Security
 import os.log
 
-class KeychainManager {
+final class KeychainManager {
     static let shared = KeychainManager()
     
     // Use consistent service name for all keychain items

bitchat/Services/NoiseEncryptionService.swift

@@ -135,7 +135,7 @@ enum EncryptionStatus: Equatable {
 /// Provides a high-level API for establishing secure channels between peers,
 /// handling all cryptographic operations transparently.
 /// - Important: This service maintains the device's cryptographic identity
-class NoiseEncryptionService {
+final class NoiseEncryptionService {
     // Static identity key (persistent across sessions)
     private let staticIdentityKey: Curve25519.KeyAgreement.PrivateKey
     public let staticIdentityPublicKey: Curve25519.KeyAgreement.PublicKey

bitchat/Services/NotificationService.swift

@@ -14,7 +14,7 @@ import UIKit
 import AppKit
 #endif
 
-class NotificationService {
+final class NotificationService {
     static let shared = NotificationService()
     
     private init() {}

bitchat/Services/PrivateChatManager.swift

@@ -10,7 +10,7 @@ import Foundation
 import SwiftUI
 
 /// Manages all private chat functionality
-class PrivateChatManager: ObservableObject {
+final class PrivateChatManager: ObservableObject {
     @Published var privateChats: [String: [BitchatMessage]] = [:]
     @Published var selectedPeer: String? = nil
     @Published var unreadMessages: Set<String> = []

bitchat/Services/UnifiedPeerService.swift

@@ -13,7 +13,7 @@ import CryptoKit
 
 /// Single source of truth for peer state, combining mesh connectivity and favorites
 @MainActor
-class UnifiedPeerService: ObservableObject, TransportPeerEventsDelegate {
+final class UnifiedPeerService: ObservableObject, TransportPeerEventsDelegate {
     
     // MARK: - Published Properties
     

bitchat/Utils/SecureLogger.swift

@@ -11,7 +11,7 @@ import os.log
 
 /// Centralized security-aware logging framework
 /// Provides safe logging that filters sensitive data and security events
-class SecureLogger {
+final class SecureLogger {
     
     // MARK: - Log Categories
     

bitchat/ViewModels/ChatViewModel.swift

@@ -90,7 +90,7 @@ import UIKit
 /// Manages the application state and business logic for BitChat.
 /// Acts as the primary coordinator between UI components and backend services,
 /// implementing the BitchatDelegate protocol to handle network events.
-class ChatViewModel: ObservableObject, BitchatDelegate {
+final class ChatViewModel: ObservableObject, BitchatDelegate {
     // Precompiled regexes and detectors reused across formatting
     private enum Regexes {
         static let hashtag: NSRegularExpression = {

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