chore: comment cleanup pass ahead of open-sourcing

Removes leftover debug scaffolding (stray Console.WriteLine/NSLog traces,
dead nick_buf_ptr, a no-op --print-config flag now implemented for real),
fixes stale/misleading comments (channel passwords are no longer a "future
M5+" feature, a wrong cross-reference, a stale TlsContext::close() mention,
an incomplete BanRecord::subject_type doc, and a smoke test pointing at a
build/m1-dev preset that no longer exists), strips internal M1-M5 milestone
jargon from comments now that the roadmap is done, trims comments that just
restated the following line, and consolidates a few "why" explanations that
were duplicated 2-3 times in the same file.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

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

@@ -185,9 +185,7 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
 
     required init?(coder: NSCoder) { fatalError() }
 
-    deinit {
-        NSLog("[VoiceCatMac] MainWindowController deinit — client and event handlers are gone")
-    }
+    deinit {}
 
     // MARK: - UI construction
 
@@ -455,10 +453,6 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         }
         ownPermissions = client.getPermissions()
 
-        NSLog("[VoiceCatMac] bootstrap: channels=%d users=%d perms{admin=%d kick=%d} currentChannelId=%u",
-              channels.count, allUsers.count,
-              ownPermissions.isAdmin, ownPermissions.canKick, currentChannelId)
-
         // Apply initial output volume (default 80% — matches Windows client)
         client.setOutputVolume(0.8)
 
@@ -477,9 +471,6 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
     // MARK: - Event handling
 
     private func handleEvent(_ event: VoiceCatEvent) {
-        NSLog("[VoiceCatMac] event type=%d result=%d userId=%u channelId=%u streamId=%u text=%@",
-              event.type.rawValue, event.result.rawValue, event.userId, event.channelId,
-              event.streamId, event.text ?? "(nil)")
         switch event.type {
         case .channelList:
             channels = client.listChannels()
@@ -1067,7 +1058,7 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         composeField.stringValue = ""
     }
 
-    // MARK: - M5: Moderation helpers
+    // MARK: - Moderation helpers
 
     private func moveUser(_ user: User) {
         let sheet = MoveUserSheet(channels: channels, currentChannelId: user.channelId)
@@ -1241,7 +1232,6 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
         presentSheet(sheet)
     }
 
-    /// Open a PM window from the user context menu.
     private func openPmWindow(_ user: User) {
         getOrOpenPmWindow(user.id)
     }
@@ -1288,17 +1278,13 @@ final class MainWindowController: NSWindowController, NSWindowDelegate {
     func windowWillClose(_ notification: Notification) {
         if let mon = pttMonitor { NSEvent.removeMonitor(mon) }
         NotificationCenter.default.removeObserver(self)
-        // Close all PM windows
         for (_, pmWin) in pmWindows { pmWin.close() }
         pmWindows.removeAll()
-        // Close settings window
         settingsWindowController?.close()
         settingsWindowController = nil
-        // Remove app menus we added
         if let item = voiceMenuItem { NSApp.mainMenu?.removeItem(item) }
         if let item = messagesMenuItem { NSApp.mainMenu?.removeItem(item) }
         if let item = adminMenuItem { NSApp.mainMenu?.removeItem(item) }
-        // Remove Settings menu item + separator from app menu
         if let appMenu = NSApp.mainMenu?.item(at: 0)?.submenu {
             if let item = settingsMenuItem { appMenu.removeItem(item) }
             // Remove the separator we inserted before Quit