Align window chrome with Sway title bars

Adds focused title-bar geometry to the window service and updates the Sway backend to derive frame data more reliably (including parent node fallback and content rect tracking for wrapped/floating views). Window chrome positioning now centers against the actual title bar instead of deco offsets, improving alignment. Also refreshes visual sizing/padding for traffic-light controls and Sway titlebar spacing to match the new chrome metrics.

shells/desktop/shell/qml/surfaces/WindowChromeSurface.qml

@@ -10,15 +10,12 @@ Window {
     readonly property bool active: WindowService.hasFocusedWindow
         && !WindowService.focusedWindowFullscreen
         && !ShellState.launcherOpen
-    readonly property int chromeX: WindowService.focusedWindowX
-        + WindowService.focusedWindowDecoX
-        + Theme.windowChromeInset
+    readonly property int chromeX: WindowService.focusedWindowX + Theme.windowChromeInset
     readonly property int chromeY: {
-        const top = WindowService.focusedWindowY + WindowService.focusedWindowDecoY
-        const decoHeight = WindowService.focusedWindowDecoHeight
-        if (decoHeight <= 0)
-            return top + 6
-        return top + Math.max(0, Math.round((decoHeight - height) / 2))
+        const barY = WindowService.focusedWindowTitleBarY
+        const barH = Math.max(WindowService.focusedWindowTitleBarHeight, height)
+        const centered = barY + Math.round((barH - height) / 2)
+        return centered - Theme.topBarHeight
     }
 
     title: qsTr("Nebula Window Chrome")