notify: correct a measured claim about the aplay fallback

The comment said aplay ignores PULSE_PROP/PIPEWIRE_PROPS. Measured:
it reaches the graph through PipeWire's ALSA plugin and carries both
carriers exactly like pw-play and paplay. Comment only.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/notify.rs

@@ -275,7 +275,9 @@ fn spawn_player(path: &Path) {
         // Ownership tag (plan §5.1). A chime is short, but it is still our
         // audio on the default sink, and an untagged one is an unowned root
         // the exclusion engine would have to reason about from scratch.
-        // `aplay` talks to ALSA and ignores both variables; harmless.
+        // Measured on this host: all three fallbacks tag correctly, `aplay`
+        // included — it reaches the graph through PipeWire's ALSA plugin,
+        // which honours `PIPEWIRE_PROPS` like any other client.
         ownership::tag_child(&mut command, ownership::NOTIFICATION_ROLE);
         let started = command.status();
         // `status()` errors only if the player binary isn't present; on a real