⚡ Bolt: Optimize audio concatenation performance

src/nodetool/media/audio/audio_helpers.py

@@ -81,10 +81,39 @@ def concatenate_audios(audios: list[AudioSegment]) -> AudioSegment:
     Returns:
         AudioSegment: The concatenated audio segment.
     """
-    concatenated_audio = AudioSegment.empty()
-    for audio in audios:
-        concatenated_audio += audio
-    return concatenated_audio
+    if not audios:
+        return AudioSegment.empty()
+
+    # ⚡ Bolt Optimization: Calculate the target parameters that pydub's += operator
+    # would implicitly upgrade to by finding the max across all input segments,
+    # convert all segments to those targets, and then do a fast O(N) byte join
+    # to avoid the O(N^2) penalty of repeated += copying.
+    first = audios[0]
+    target_sample_width = first.sample_width
+    target_frame_rate = first.frame_rate
+    target_channels = first.channels
+
+    for a in audios[1:]:
+        target_sample_width = max(target_sample_width, a.sample_width)
+        target_frame_rate = max(target_frame_rate, a.frame_rate)
+        target_channels = max(target_channels, a.channels)
+
+    raw_data_list = []
+    for a in audios:
+        if a.sample_width != target_sample_width:
+            a = a.set_sample_width(target_sample_width)
+        if a.frame_rate != target_frame_rate:
+            a = a.set_frame_rate(target_frame_rate)
+        if a.channels != target_channels:
+            a = a.set_channels(target_channels)
+        raw_data_list.append(a.raw_data)
+
+    res = first._spawn(b"".join(raw_data_list), overrides={
+        "sample_width": target_sample_width,
+        "frame_rate": target_frame_rate,
+        "channels": target_channels
+    })
+    return res
 
 
 def remove_silence(