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/windows/VoiceCat.App/Notifications/SoundEvent.cs

@@ -7,17 +7,17 @@ namespace VoiceCat.App.Notifications;
 /// </summary>
 public enum SoundEvent
 {
-    ChannelJoin,    // another user joined my channel
-    ChannelLeave,   // another user left my channel
+    ChannelJoin,
+    ChannelLeave,
     ChannelRecv,    // channel text message from someone else
     ChannelSent,    // channel text message I sent
-    PmRecv,         // private message received
-    PmSent,         // private message I sent
-    Login,          // connected / authenticated
-    Logout,         // clean disconnect
-    ConnectionLost, // unexpected disconnect
-    VoiceOn,        // my microphone stream started
-    VoiceOff,       // my microphone stream stopped
+    PmRecv,
+    PmSent,
+    Login,
+    Logout,
+    ConnectionLost,
+    VoiceOn,
+    VoiceOff,
     VaStart,        // my voice-activity began (off by default)
     VaStop,         // my voice-activity ended (off by default)
     Ptt,            // push-to-talk engaged (off by default)