Fix/macos audio crash

[guidiguidi]

Summary

This PR improves macOS smoothness by reducing two common sources of micro-stutters:

• Audio device change “refresh storms” from CoreAudio notifications.
• Excessive per-tick work while scrolling the chat list.

What changed

• lib_webrtc (macOS):
  • Added lazy subscription to CoreAudio listeners.
  • Debounced default device + device list change handling, coalescing bursts into a single refresh.
• Dialogs chat list:
  • Coalesced visible-range updates during scroll to avoid doing heavier preload/load-more logic on every scroll tick.
• tgcalls (macOS):
  • Safer AudioDeviceModule creation (guarded against edge cases) and a small cache for audio-input availability checks to avoid repeated expensive queries.

Why

On macOS (especially newer versions), CoreAudio can emit bursts of device-related notifications even without user action. Forcing full device refreshes immediately can lead to periodic UI micro-stutters.
Similarly, chat list scrolling can trigger frequent visible-range updates; coalescing the heavy part improves perceived FPS and reduces jank.

Test plan

• Scroll chat list fast for ~20–30 seconds → smoother scrolling, less jank
• Plug/unplug or switch input/output device → device list updates correctly (no refresh storm)
• (Optional) Start a call / open call settings → audio devices still initialize correctly

Notes

• This is a performance-focused change; behavior should remain the same, with small expected delays (~tens/hundreds of ms) during bursty device-change events due to debouncing.