Mono-per-track: a new note releases the track's previous one (v0.10.0)

A sustaining note held with no explicit note-off used to pile up until
voice-stealing killed it. Now, when a note appears under the playhead on a
track, that track's still-held note is released automatically, so a line moves
note-to-note like a real monophonic voice.

Each sequencer voice carries an ownerTrack tag (the lane+track that started it),
and triggerCell calls releaseTrackVoices(trackKey) before playing a new note. It
releases only voices this track owns and only gated (still-held) ones, so chords
built across several tracks on the same bus keep sounding and release tails ring
out. Uses note-off (not kill) for a click-free legato hand-off. Arp voices are
unowned and keep self-managing as mono-per-bus.

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

app/build.gradle.kts

@@ -22,8 +22,8 @@ android {
         // (android.media.midi) and AAudio low-latency audio we rely on.
         minSdk = 26
         targetSdk = 34
-        versionCode = 26
-        versionName = "0.9.1"
+        versionCode = 27
+        versionName = "0.10.0"
 
         // We provide our own instrumentation runner if/when tests are added.
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"