style: rustfmt the 0.6.2 additions (A17b + version-in-UI)

CI's fmt --check caught that Codex's hand-written additions in these two files
weren't rustfmt-formatted (the senior gate ran clippy + tests but not
fmt --check). Pure line-wrapping, no logic change. Keeps the crate fmt-clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/audio/multitrack.rs

@@ -380,7 +380,11 @@ impl MultitrackRecorder {
         let batch = CycleBatch {
             new_peers: pending.new_peers,
             mic_frame,
-            mix_frame: if self.with_mix { pending.mix_frame } else { None },
+            mix_frame: if self.with_mix {
+                pending.mix_frame
+            } else {
+                None
+            },
             peer_frames: pending.peer_frames,
         };
         match self.batch_tx.try_send(batch) {
@@ -560,9 +564,15 @@ mod tests {
         assert_eq!(state.cycles_written, 3);
         assert_eq!(state.mic.samples.len(), 3 * frame);
         assert_eq!(state.mix.as_ref().unwrap().samples.len(), 3 * frame);
-        assert_eq!(&state.mix.as_ref().unwrap().samples[2 * frame..], &[0, 0, 0]);
+        assert_eq!(
+            &state.mix.as_ref().unwrap().samples[2 * frame..],
+            &[0, 0, 0]
+        );
         assert_eq!(state.peers.get(&early).unwrap().samples.len(), 3 * frame);
-        assert_eq!(&state.peers.get(&early).unwrap().samples[2 * frame..], &[2, 2, 2]);
+        assert_eq!(
+            &state.peers.get(&early).unwrap().samples[2 * frame..],
+            &[2, 2, 2]
+        );
         assert_eq!(
             state.peers.get(&late).unwrap().samples,
             vec![0, 0, 0, 0, 0, 0, 7, 7, 7],