docs(ios): drop stale debug comments + TeamTalk refs from audio router

After the stereo-mic/A2DP debugging settled, the iOS audio code carried
leftover TeamTalk5 comparison notes, source-line citations, TEMP DIAGNOSTIC
markers, and "this was the bug" narratives that no longer help. Reworded
those to state the current rules; kept the comments that document real
constraints (the setPreferredInputNumberOfChannels(2) trap, the re-entrancy
guard, the ma_context no-session-management config).

Comment-only — no behavior change. core builds, ctest --preset dev 21/21.

clients/apple/Sources/VoiceCatCore/VoiceCatClient.swift

@@ -349,9 +349,8 @@ public final class VoiceCatClient {
     /// AVAudioSession (setCategory, setPreferredInput, setPreferredPolarPattern, etc.) so the
     /// core's devices reopen against the new route. Unlike `audioSuspend()`/`audioResume()`
     /// (which only stop/start the existing devices, leaving them bound to the route that was
-    /// active when they were opened), this fully re-initializes them. Mirrors TeamTalk5's
-    /// closeSoundDevices()/initSoundInputDevice()/initSoundOutputDevice() pattern. Safe to
-    /// call when the engine is not running (it will just start it).
+    /// active when they were opened), this fully re-initializes them. Safe to call when the
+    /// engine is not running (it will just start it).
     @discardableResult
     public func audioRestart() -> VoiceCatResult {
         VoiceCatResult(vc_audio_restart(handle))