fix(audio): bump generation on paused device reopen to stop spurious audio:ended

Third defence for #1094: on a device change while paused/stopped,
reopen_output_stream stopped the old sink without bumping the engine
generation (the bump only happened on a successful internal resume). The
still-running progress task could then flip done_flag and emit a spurious
audio:ended, which the frontend turns into a restart. Bump the generation
before sink.stop() in the non-playing case so the progress task bails out;
the active-playback path keeps bumping inside try_resume_after_device_change.

(cherry picked from commit 9034882bf6)

src-tauri/crates/psysonic-audio/src/device_watcher.rs

@@ -82,6 +82,15 @@ pub(crate) async fn reopen_output_stream(
     if !opened {
         return false;
     }
+    // When we're not actively playing (paused/stopped), bump the generation
+    // before stopping the old sink so the still-running progress task sees the
+    // mismatch and bails out instead of emitting a spurious `audio:ended` —
+    // which would otherwise trigger a frontend restart of paused playback
+    // (#1094). The active-playback path bumps inside
+    // `try_resume_after_device_change`, so only guard the non-playing case here.
+    if !snapshot.is_playing {
+        engine.generation.fetch_add(1, Ordering::SeqCst);
+    }
     if let Some(s) = current.lock().unwrap().sink.take() {
         s.stop();
     }