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/player/qml/StemPlayer/XField.qml

@@ -0,0 +1,17 @@
+import QtQuick
+import QtQuick.Controls.Basic
+
+TextField {
+    font.family: uiFont
+    font.pixelSize: X.fsUi
+    color: X.ink
+    selectByMouse: true
+    selectionColor: "#B7D7C4"
+    selectedTextColor: "#000000"
+    leftPadding: 5
+    rightPadding: 5
+    topPadding: 2
+    bottomPadding: 2
+    implicitHeight: 22
+    background: Rectangle { color: "#FFFFFF"; border.color: parent.activeFocus ? X.green : "#ABABAB" }
+}