fix: linux arm64 build error (Dup2 is not available, use unix.Dup2)

cmd/tui/noise_linux.go

@@ -4,7 +4,8 @@ package main
 
 import (
 	"os"
-	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
 func redirectStderr(f *os.File) {
@@ -12,12 +13,12 @@ func redirectStderr(f *os.File) {
 		// Silence altogether if no debug file
 		null, err := os.OpenFile(os.DevNull, os.O_WRONLY, 0)
 		if err == nil {
-			syscall.Dup2(int(null.Fd()), int(os.Stderr.Fd()))
+			_ = unix.Dup2(int(null.Fd()), int(os.Stderr.Fd()))
 		}
 		return
 	}
 
 	// Redirect fd 2 (stderr) to our debug file
 	// This captures C-level library noise (ALSA, PortAudio) into the log
-	syscall.Dup2(int(f.Fd()), int(os.Stderr.Fd()))
+	_ = unix.Dup2(int(f.Fd()), int(os.Stderr.Fd()))
 }