Move synth pitch modulation to control rate — fix playback hiccups (v0.4.4)

On-device profiling (worst case: 4 channels x 3 oscillators + cutoff & pitch
modulation, dense pattern at 200 BPM) showed the render callback averaging 2.8ms
against a 2.0ms budget with continuous xruns — the hiccups. The cost was the
per-sample Math.pow used for pitch modulation across 3 oscillators x many voices.

Recompute modulated oscillator pitch at control rate (every 16 samples, like the
filter cutoff) instead of per sample; LFO/envelopes move slowly enough that this
is inaudible. Render dropped to ~1.27ms avg with zero new xruns. No crashes under
load (the ConcurrentHashMap + stable SVF filter fixes from 0.4.3 hold).

Patch bump to 0.4.4 (versionCode 11).

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 = 10
-        versionName = "0.4.3"
+        versionCode = 11
+        versionName = "0.4.4"
 
         // We provide our own instrumentation runner if/when tests are added.
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"