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/DashedFrame.qml

@@ -0,0 +1,25 @@
+import QtQuick
+import QtQuick.Shapes
+
+// Static dashed rounded border (geometry built once; only opacity animates).
+Shape {
+    id: s
+    property color color: Theme.accentGlow
+    property real radius: 12
+    property real lineWidth: 2
+    preferredRendererType: Shape.CurveRenderer
+    ShapePath {
+        strokeColor: s.color
+        strokeWidth: s.lineWidth
+        strokeStyle: ShapePath.DashLine
+        dashPattern: [5, 4]
+        fillColor: "transparent"
+        PathRectangle {
+            x: s.lineWidth / 2
+            y: s.lineWidth / 2
+            width: s.width - s.lineWidth
+            height: s.height - s.lineWidth
+            radius: s.radius
+        }
+    }
+}