Layouts, iPad-style rendering, taps, shift and layers

- JSON layouts (en-US, sv-SE inheriting number/symbol layers via base)
- LayoutModel + KeyGeometry: proportional rows, nearest-key hit testing
- KeyboardSurface: multi-pointer touch/mouse routing to the controller
- KeyboardController + ShiftState: iOS shift/caps-lock, layers, globe, dismiss
- QML view with light/dark iPad palette and drag handle
- DevHooks: SLOPOSK_AUTOTYPE, SLOPOSK_SCREENSHOT for headless checks
- Unit tests for shift, loader, geometry and controller

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

qml/Main.qml

@@ -1,45 +1,34 @@
 import QtQuick
-import QtQuick.Controls
+import Sloposk
 
-// Spike UI: proves text commits, keysyms and dragging. Replaced by the real
-// keyboard in milestone 2.
 Window {
     id: root
 
-    required property var backend
-    property var placement: null
+    required property LayoutModel layoutModel
+    required property KeyboardController controller
+    property var placement: null // FloatingWindow, set from C++
 
-    width: 720
-    height: 120
+    width: 1000
+    height: 340
     visible: false
-    color: "#d1d3d9"
+    color: "transparent"
 
     Rectangle {
-        id: handle
-        anchors { horizontalCenter: parent.horizontalCenter; bottom: parent.bottom; bottomMargin: 6 }
-        width: 120; height: 6; radius: 3
-        color: "#8e8e93"
+        anchors.fill: parent
+        radius: Theme.windowRadius
+        color: Theme.background
 
-        DragHandler {
-            target: null
-            margin: 12
-            property point last
-            onActiveChanged: last = centroid.scenePressPosition
-            onCentroidChanged: {
-                if (!active || !root.placement)
-                    return
-                const p = centroid.scenePosition
-                root.placement.moveBy(p.x - last.x, p.y - last.y)
-            }
+        Keyboard {
+            anchors { left: parent.left; right: parent.right; top: parent.top; bottom: handle.top }
+            anchors.margins: 2
+            model: root.layoutModel
+            controller: root.controller
+        }
+
+        DragHandle {
+            id: handle
+            anchors { left: parent.left; right: parent.right; bottom: parent.bottom }
+            onMoved: (dx, dy) => root.placement?.moveBy(dx, dy)
         }
     }
-
-    Row {
-        anchors.centerIn: parent
-        spacing: 8
-        Button { text: "héllo👍"; focusPolicy: Qt.NoFocus; onClicked: root.backend.commitText(text) }
-        Button { text: "⌫"; focusPolicy: Qt.NoFocus; onClicked: root.backend.sendKeysym(0xff08) }
-        Button { text: "⏎"; focusPolicy: Qt.NoFocus; onClicked: root.backend.sendKeysym(0xff0d) }
-        Label { anchors.verticalCenter: parent.verticalCenter; text: root.backend.active ? "active" : "inactive" }
-    }
 }