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/FormulaBar.qml

@@ -0,0 +1,51 @@
+import QtQuick
+
+// Name box, the ✕ ✓ fx buttons, and the formula of the active cell.
+Rectangle {
+    id: fb
+    property var win: Window.window
+    height: 30
+    color: "#FFFFFF"
+    Rectangle { anchors.bottom: parent.bottom; width: parent.width; height: 1; color: X.ribbonLine }
+
+    Rectangle {
+        id: nameBox
+        x: 4
+        y: 4
+        width: 110
+        height: 22
+        border.color: "#C6C6C6"
+        T {
+            x: 5
+            height: parent.height
+            width: parent.width - 20
+            text: fb.win.multiSel ? (fb.win.selBottom - fb.win.selTop + 1) + "R x " + (Math.abs(fb.win.curCol - fb.win.anchorCol) + 1) + "C"
+                                  : X.colName(fb.win.curCol) + (fb.win.curRow + 2)
+        }
+        Ico { anchors.right: parent.right; anchors.rightMargin: 4; anchors.verticalCenter: parent.verticalCenter; name: "dropdown"; size: 10 }
+    }
+    Row {
+        x: nameBox.x + nameBox.width + 10
+        height: parent.height
+        spacing: 12
+        Ico { anchors.verticalCenter: parent.verticalCenter; name: "cancel"; size: 14; opacity: 0.35 }
+        Ico { anchors.verticalCenter: parent.verticalCenter; name: "check"; size: 14; opacity: 0.35 }
+        Ico { anchors.verticalCenter: parent.verticalCenter; name: "function"; size: 18 }
+    }
+    Rectangle {
+        x: nameBox.x + nameBox.width + 92
+        y: 4
+        width: parent.width - x - 6
+        height: 22
+        border.color: "#C6C6C6"
+        T {
+            x: 6
+            width: parent.width - 12
+            height: parent.height
+            font.family: cellFont
+            font.pixelSize: 14
+            color: "#000000"
+            text: fb.win.formulaText
+        }
+    }
+}