Rename to TNCat, add chip chase, G-codes and a Wayland layout

The project is now TNCat, after HEIDENHAIN's TNC controls. Binary, QML module
URI, settings path, bundle id and .desktop entry follow; the environment
switches are TNCAT_*.

Entertainment: a curled steel chip skitters in every minute or two, the cat
runs it down and bats it away a few times before sitting back looking pleased.
Mood changes flash the matching machine code above its head, G00 for a sprint,
G01 for a stroll, M08 while it washes, G28 for a stretch, M30 for a nap.

Window handling was split into two layouts. X11 and macOS keep one small window
per object, positioned by the app. Wayland gets a screen-filling overlay whose
input region is masked down to the cat, since a Wayland client cannot place its
own window. Overlay mode is automatic there and available elsewhere via
TNCAT_OVERLAY=1.

Also adds a ground-line setting so the cat can walk above a softkey row.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

qml/SettingsWindow.qml

@@ -2,7 +2,7 @@ pragma ComponentBehavior: Bound
 import QtQuick
 import QtQuick.Controls.Basic
 import QtQuick.Layouts
-import Workcat
+import TNCat
 
 Window {
     id: win
@@ -20,10 +20,10 @@ Window {
     ]
 
     width: 440
-    height: 600
+    height: 700
     minimumWidth: 380
-    minimumHeight: 520
-    title: qsTr("Workcat")
+    minimumHeight: 600
+    title: qsTr("TNCat")
     color: "#faf7f2"
     flags: Qt.Dialog | Qt.WindowStaysOnTopHint
 
@@ -35,20 +35,24 @@ Window {
         RowLayout {
             Layout.fillWidth: true
             spacing: 16
-            Cat {
+            Loader {
                 Layout.preferredWidth: 110
                 Layout.preferredHeight: 99
-                coat: win.settings.coat
-                mood: "sitting"
-                petted: previewHover.hovered
-                HoverHandler { id: previewHover }
+                active: win.visible
+                sourceComponent: Cat {
+                    coat: win.settings.coat
+                    mood: "sitting"
+                    showCodes: false
+                    petted: previewHover.hovered
+                    HoverHandler { id: previewHover }
+                }
             }
             ColumnLayout {
                 Layout.fillWidth: true
                 spacing: 4
                 Label {
                     Layout.fillWidth: true
-                    text: qsTr("Workcat")
+                    text: qsTr("TNCat")
                     font.pixelSize: 26
                     font.bold: true
                     color: "#2f2a36"
@@ -122,6 +126,22 @@ Window {
                 onMoved: win.settings.walkSpeed = value
             }
 
+            Label { text: qsTr("Ground line") }
+            RowLayout {
+                Layout.fillWidth: true
+                Slider {
+                    id: marginSlider
+                    Layout.fillWidth: true
+                    from: 0; to: 600; stepSize: 10
+                    value: win.settings.bottomMargin
+                    onMoved: win.settings.bottomMargin = value
+                }
+                Label {
+                    Layout.preferredWidth: 54
+                    text: qsTr("%1 px").arg(Math.round(marginSlider.value))
+                }
+            }
+
             Label { text: qsTr("Eyes") }
             Switch {
                 text: qsTr("Follow the mouse")
@@ -129,6 +149,20 @@ Window {
                 onToggled: win.settings.followCursor = checked
             }
 
+            Label { text: qsTr("Codes") }
+            Switch {
+                text: qsTr("Show G-code above the cat")
+                checked: win.settings.showCodes
+                onToggled: win.settings.showCodes = checked
+            }
+
+            Label { text: qsTr("Chips") }
+            Switch {
+                text: qsTr("Let a chip skitter past now and then")
+                checked: win.settings.chipsEnabled
+                onToggled: win.settings.chipsEnabled = checked
+            }
+
             Label { text: qsTr("Cat") }
             Switch {
                 text: checked ? qsTr("Napping") : qsTr("Awake")
@@ -148,6 +182,7 @@ Window {
                 Button { text: qsTr("Stretch"); onClicked: win.cat.doTrick(CatController.Stretching) }
                 Button { text: qsTr("Dash");    onClicked: win.cat.doTrick(CatController.Running) }
                 Button { text: qsTr("Nap");     onClicked: win.cat.doTrick(CatController.Sleeping) }
+                Button { text: qsTr("Toss a chip"); onClicked: win.cat.tossChip() }
             }
         }