v1.2.9 - App audio capture fix

Bug Fixes

• App audio capture now works for Spotify, Apple Music, and other apps — IAudioClient::Initialize was missing AUDCLNT_STREAMFLAGS_LOOPBACK_PROCESSLOOPBACK, causing all process-loopback streams to fail silently with no audio output
• App audio mute keybind button no longer shows garbled text during key capture — the countdown was being overwritten every 80ms by the UI refresh ticker