Feat: cleanup

src/engine/audio.rs

@@ -1,3 +1,5 @@
+//! Audio output stream (cpal) and FFT spectrum analysis.
+
 use ringbuf::{traits::*, HeapRb};
 use rustfft::{num_complex::Complex, FftPlanner};
 use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
@@ -173,8 +175,8 @@ impl SpectrumAnalyzer {
 
 pub struct AnalysisHandle {
     running: Arc<AtomicBool>,
-    #[allow(dead_code)]
-    thread: Option<JoinHandle<()>>,
+    // Held to keep the thread alive until this handle is dropped.
+    _thread: Option<JoinHandle<()>>,
 }
 
 impl Drop for AnalysisHandle {
@@ -202,7 +204,7 @@ pub fn spawn_analysis_thread(
 
     let handle = AnalysisHandle {
         running,
-        thread: Some(thread),
+        _thread: Some(thread),
     };
 
     (producer, handle)