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/iOS/VoiceCatiOS/Views/PerUserTuningView.swift

@@ -48,7 +48,6 @@ struct PerUserTuningView: View {
             }
         }
         .onAppear {
-            // Load from first stream if available
             let streams = streamsForUser
             if let first = streams.first {
                 let (_, state) = session.client.getRemoteStream(userId: user.id, streamId: first.id)