StemRoller: desktop stem separator, Android stems player, and server daemons

- stemroller/: PySide6/QML desktop app and player for separating music into stems
- android/: Plex music player that plays per-stem mixes, with Android Auto support,
  a graphic + parametric (Equalizer APO-style) EQ, and offline downloads
- server/: stemserve (serves stems to the app) and stemd (separates the library on
  the server's GPU, with "Stem Now" priority requests)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

stemroller/qml/StemRoller/Txt.qml

@@ -0,0 +1,10 @@
+import QtQuick
+
+Text {
+    color: Theme.textHi
+    font.family: Theme.fontFamily
+    font.pixelSize: Theme.fs14
+    renderType: Text.NativeRendering
+    elide: Text.ElideRight
+    verticalAlignment: Text.AlignVCenter
+}