Swift 6 Migration (#5733)

* Enable Swift 6.2 with default main actor isolation for the app target

Turn on SWIFT_VERSION 6.2, SWIFT_APPROACHABLE_CONCURRENCY and SWIFT_DEFAULT_ACTOR_ISOLATION = MainActor for the ElementX target, matching the NSE and Share Extension (which already use 6.2 without the main actor default).

# Conflicts:
#	ElementX.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

* Update the code generation templates for Swift 6

Emit nonisolated/@unchecked Sendable mocks and nonisolated string enums, and mark async mock methods @concurrent so they keep suspending like the real implementations (otherwise intermediate states are unobservable in tests). Includes the regenerated mocks and strings.

# Conflicts:
#	ElementX/Sources/Mocks/Generated/GeneratedMocks.swift

* Make the data layer and services nonisolated and Sendable

Annotate the value-type models, Rust SDK proxy wrappers, timeline item graph, settings, logging and NSE-shared types as nonisolated, and conform the service protocols to Sendable so their existentials can cross isolation boundaries. These types run off the main actor and no longer inherit the target's default main actor isolation.

* Adopt the new isolation across call sites, mocks and signatures

Update call sites, closure signatures and mock configuration helpers to match the nonisolated/Sendable data layer, including the main actor isolated mock inits and the @Sendable filter on recentlyVisitedRooms.

^ Conflicts:
^	ElementX/Sources/Services/SecureBackup/SecureBackupController.swift

* Remove redundant @MainActor annotations

With the app target defaulting to main actor isolation, the explicit @MainActor on view models, coordinators, views and their protocols is no longer required.

* Fix concurrency hotspots surfaced by the migration

Resolve the room summary main-thread deadlock by moving diff processing onto AsyncStreams, add the SDKListener.onMainActor FIFO bridge for SDK callbacks, hop KVO/timer/UIKit callbacks to the main actor via assumeIsolated, add isolated deinits, and apply the few justified nonisolated(unsafe) escapes for queue-confined Apple APIs.

* Fix the unit tests for Swift 6 concurrency

Hop the waitForConfirmation body onto the caller's actor (Swift Testing runs confirmation closures off-actor), and adjust the affected suites and async signatures.

* offload diffs on concurrent threads instead of main actor

* make room info protocols sendable

* use a task group for fetching data so that everything runs concurrently in the TextRoomTimelineView when getting the preview.

* use the generic onMainActor implementation, which already makes a stream and send the continuation on the main actor.

* small pr comments issues being addressed

* update enterprise

* Update StaticCode to 1.1.0 and specify the required Swift isolation.

* fix ElementCallServiceTests

* update enterprise

* re-generate mocks

* update enterprise

* enterprise new code conformed to swift 6

---------

Co-authored-by: Doug <douglase@element.io>

ElementX/Sources/Services/Audio/Recorder/AudioRecorder.swift

@@ -12,14 +12,16 @@ import Combine
 import Foundation
 import UIKit
 
-private enum InternalAudioRecorderState: Equatable {
+private nonisolated enum InternalAudioRecorderState: Equatable {
     case recording
     case suspended
     case stopped
     case error(AudioRecorderError)
 }
 
-class AudioRecorder: AudioRecorderProtocol {
+/// All mutable state is confined to the serial `dispatchQueue` (with the realtime tap
+/// reading converter/file that are set up before the engine starts), hence `@unchecked`.
+nonisolated class AudioRecorder: AudioRecorderProtocol, @unchecked Sendable {
     private let audioSession: AudioSessionProtocol
     private var audioEngine: AVAudioEngine?
     private var mixer: AVAudioMixerNode?
@@ -143,7 +145,7 @@ class AudioRecorder: AudioRecorderProtocol {
         return try AVAudioFile(forWriting: recordingURL, settings: settings)
     }
     
-    private func startRecording(audioFileURL: URL, completion: @escaping (Result<Void, AudioRecorderError>) -> Void) {
+    private func startRecording(audioFileURL: URL, completion: @escaping @Sendable (Result<Void, AudioRecorderError>) -> Void) {
         dispatchQueue.async { [weak self] in
             guard let self, !self.stopped else {
                 completion(.failure(.recordingCancelled))
@@ -220,7 +222,7 @@ class AudioRecorder: AudioRecorderProtocol {
         }
     }
     
-    private func stopRecording(completion: @escaping () -> Void) {
+    private func stopRecording(completion: @escaping @Sendable () -> Void) {
         dispatchQueue.async { [weak self] in
             defer {
                 completion()
@@ -247,7 +249,7 @@ class AudioRecorder: AudioRecorderProtocol {
         releaseAudioSession()
     }
     
-    private func deleteRecording(completion: @escaping () -> Void) {
+    private func deleteRecording(completion: @escaping @Sendable () -> Void) {
         dispatchQueue.async { [weak self] in
             defer {
                 completion()
@@ -287,9 +289,12 @@ class AudioRecorder: AudioRecorderProtocol {
             }
             
             // Convert the buffer
+            // The block type is `@Sendable` but `convert(to:error:withInputFrom:)`
+            // invokes it synchronously on this same thread, the buffer never crosses.
+            nonisolated(unsafe) let inputBufferForConversion = buffer
             let inputBlock: AVAudioConverterInputBlock = { _, outStatus in
                 outStatus.pointee = AVAudioConverterInputStatus.haveData
-                return buffer
+                return inputBufferForConversion
             }
             
             var conversionError: NSError?

ElementX/Sources/Services/Audio/Recorder/AudioRecorderProtocol.swift

@@ -9,7 +9,7 @@
 import Combine
 import Foundation
 
-enum AudioRecorderError: Error, Equatable {
+nonisolated enum AudioRecorderError: Error, Equatable {
     case unsupportedAudioFormat
     case audioSessionFailure
     case audioEngineFailure
@@ -19,13 +19,13 @@ enum AudioRecorderError: Error, Equatable {
     case recordPermissionNotGranted
 }
 
-enum AudioRecorderAction {
+nonisolated enum AudioRecorderAction {
     case didStartRecording
     case didStopRecording
     case didFailWithError(error: AudioRecorderError)
 }
 
-protocol AudioRecorderProtocol: AnyObject {
+nonisolated protocol AudioRecorderProtocol: AnyObject, Sendable {
     var actions: AnyPublisher<AudioRecorderAction, Never> { get }
     var currentTime: TimeInterval { get }
     var isRecording: Bool { get }

ElementX/Sources/Services/Audio/Recorder/AudioRecorderState.swift

@@ -16,7 +16,6 @@ enum AudioRecorderRecordingState {
     case error
 }
 
-@MainActor
 class AudioRecorderState: ObservableObject, Identifiable {
     let id = UUID()