feat(clients): event sound effects + optional text-to-speech

Add audible cues and optional spoken announcements for session events
(join/leave, channel + PM sent/recv, login, logout/connection-lost,
mic on/off, voice-activity, PTT) across all three clients, driven off
the shared C ABI vc_event stream so the mapping stays consistent.

TTS is off by default; when enabled it announces events and reads
message/PM bodies aloud. Master toggles + a sound-volume slider; the
per-utterance voice-activity and PTT cues default off. WAVs ship from
assets/sounds/.

Windows (built + verified): new VoiceCat.App/Notifications/ layer
(FeedbackSettings -> %AppData%\VoiceCat\feedback.json, SoundPlayerPool
via System.Media.SoundPlayer, SpeechAnnouncer via Prismatoid 0.3.0,
EventFeedback dispatcher); MainForm hooks; NotificationSettingsForm
under Settings > Notifications; csproj adds the Prismatoid PackageRef
and copies the WAVs into sounds\.

macOS + iOS (written, not yet built -- needs a Mac): shared
VoiceCatCore/Feedback/ (SoundEvent, EventFeedback = AVAudioPlayer pool
+ native AVSpeechSynthesizer, FeedbackSettings over UserDefaults); WAVs
bundled via Package.swift resources (.process). Hooks in SessionState/
AppState (iOS) and MainWindowController (macOS); settings UI in
SettingsView (iOS) and SettingsWindowController (macOS).

No core/server code touched; ctest --preset dev unaffected.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

clients/apple/macOS/VoiceCatMac/Windows/MainWindowController.swift

@@ -35,6 +35,7 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
     private var screenAudioSelection: ScreenAudioSelection = .default
     internal var pttKeyCode: UInt16 = 0x60  // F8
     private var pttMonitor: Any?
+    private var pttEngaged = false  // guards the PTT cue against key-repeat
     private var serverMuted = false
     private var serverDeafened = false
     private var channelTree: [ChannelNode] = []
@@ -343,7 +344,11 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         pttMonitor = NSEvent.addLocalMonitorForEvents(matching: [.keyDown, .keyUp]) { [weak self] event in
             guard let self, self.selectedInputMode == .pushToTalk,
                   self.micStreamId != 0, event.keyCode == self.pttKeyCode else { return event }
-            self.client.setPushToTalk(event.type == .keyDown)
+            let down = event.type == .keyDown
+            self.client.setPushToTalk(down)
+            // Cue only on the press transition — key-down auto-repeats while held.
+            if down && !self.pttEngaged { EventFeedback.shared.play(.ptt) }
+            self.pttEngaged = down
             return nil
         }
 
@@ -385,6 +390,8 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         buildMessagesMenu()
         buildAdminMenu()
         addActivity("Connected to server as \(nickname)")
+        EventFeedback.shared.play(.login)
+        EventFeedback.shared.speak("Connected")
     }
 
     // MARK: - Event handling
@@ -415,6 +422,8 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
             refreshChannelTree(); refreshUserList()
             if event.channelId == currentChannelId && event.userId != selfUserId {
                 addActivity("\(u.nickname) joined the channel")
+                EventFeedback.shared.play(.channelJoin)
+                EventFeedback.shared.speak("\(u.nickname) joined")
             }
 
         case .userLeft:
@@ -423,7 +432,11 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
             users.removeValue(forKey: event.userId)
             talkingUsers.remove(event.userId)
             refreshChannelTree(); refreshUserList()
-            if wasHere { addActivity("\(nick) left the channel") }
+            if wasHere {
+                addActivity("\(nick) left the channel")
+                EventFeedback.shared.play(.channelLeave)
+                EventFeedback.shared.speak("\(nick) left")
+            }
             if let pmWin = pmWindows[event.userId] {
                 pmWin.appendActivity("\(nick) disconnected from server")
             }
@@ -473,6 +486,9 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
             let talking = event.u32a == 1
             if talking { talkingUsers.insert(event.userId) } else { talkingUsers.remove(event.userId) }
             refreshUserList()
+            if event.userId == selfUserId {
+                EventFeedback.shared.play(talking ? .vaStart : .vaStop)
+            }
             if talking && event.userId != selfUserId,
                let u = users[event.userId], u.channelId == currentChannelId {
                 addActivity("\(u.nickname) started talking")
@@ -521,21 +537,28 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
             time = DateFormatter.localizedString(from: Date(), dateStyle: .none, timeStyle: .short)
         }
         let sender = nickname(for: event.userId)
+        let isSelf = event.userId == selfUserId
+        let body = event.text ?? ""
 
         if event.textScope == .private {
             // Route PMs to per-conversation windows. For our own outgoing PM, ev.channelId
             // carries the recipient user ID; for incoming, ev.userId is the sender.
-            let otherId = event.userId == selfUserId ? event.channelId : event.userId
+            let otherId = isSelf ? event.channelId : event.userId
             let win = getOrOpenPmWindow(otherId)
-            win.appendMessage(time: time, isSelf: event.userId == selfUserId, sender: sender,
-                              text: event.text ?? "")
-            if event.userId != selfUserId {
+            win.appendMessage(time: time, isSelf: isSelf, sender: sender, text: body)
+            EventFeedback.shared.play(isSelf ? .pmSent : .pmRecv)
+            if !isSelf {
                 addActivity("Private message from \(sender)")
+                EventFeedback.shared.speak("Private message from \(sender): \(body)")
             }
         } else {
-            let line = "[\(time)] \(sender): \(event.text ?? "")\n"
+            let line = "[\(time)] \(sender): \(body)\n"
             logTextView.textStorage?.append(NSAttributedString(string: line))
             logTextView.scrollToEndOfDocument(nil)
+            EventFeedback.shared.play(isSelf ? .channelSent : .channelRecv)
+            if !isSelf {
+                EventFeedback.shared.speak("\(sender): \(body)")
+            }
         }
     }
 
@@ -607,6 +630,8 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         let msg = event.text.map { "Disconnected: \($0)" } ?? "Disconnected from server."
         statusLabel.stringValue = msg
         addActivity(msg)
+        EventFeedback.shared.play(event.result == .ok ? .logout : .connectionLost)
+        EventFeedback.shared.speak(event.result == .ok ? "Disconnected" : "Connection lost")
         channelTree = []; channelOutlineView.reloadData()
         displayedUsers = []; userTableView.reloadData()
         users.removeAll(); talkingUsers.removeAll()
@@ -689,6 +714,7 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
                 }
                 setVoiceJoinedState(true)
                 addActivity("Joined voice — microphone active")
+                EventFeedback.shared.play(.voiceOn)
                 NSAccessibility.post(element: logTextView, notification: .announcementRequested,
                                      userInfo: [.announcement: "Joined voice", .priority: NSAccessibilityPriorityLevel.medium])
             } else {
@@ -701,6 +727,7 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
             settingsWindowController?.resetLevel()
             setVoiceJoinedState(false)
             addActivity("Left voice")
+            EventFeedback.shared.play(.voiceOff)
         }
     }