Gaze mode: the mouse only corrects, and left-then-right right-clicks

POINTER_GAZE_MOUSE_MOVE=held, the default (the Gaze page's Mouse movement
switch, with why it's on): while the gaze has the pointer, moving the mouse
does nothing; it moves the pointer only while a button is held, as a
correction. A bumped or drifting mouse can't pull the pointer off what you're
looking at, and every mouse move is a correction, so lessons aren't polluted by
mouse moves to somewhere else. With the gaze stale for a second, in a game, or
with the headset off, the mouse moves the pointer as usual. "free" is the old
behaviour.

Pressing the right button while the left one's press is held back right-clicks
where the pointer is instead (correct with the left, then right-click); both
releases are then nothing. Meta+J then Meta+K stays a drag.

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

input-settings/main.qml

@@ -890,6 +890,30 @@ Kirigami.ApplicationWindow {
                         }
                     }
                 }
+                Controls.Switch {
+                    Kirigami.FormData.label: "Mouse movement:"
+                    text: "Only while a button is held (recommended)"
+                    checked: backend.gazeMouseHeld
+                    onToggled: backend.setGazeMouseHeld(checked)
+                }
+                Controls.Label {
+                    Layout.maximumWidth: Kirigami.Units.gridUnit * 30
+                    wrapMode: Text.WordWrap
+                    text: backend.gazeMouseHeld
+                          ? "Your eyes move the pointer, so moving the mouse on its own does nothing. To fix a click "
+                            + "that's a little off, press and hold the left button: the pointer stops where you're "
+                            + "looking. Move the mouse onto what you meant and let go to click there, or press the "
+                            + "right button instead to right-click there. It's on because a bumped or drifting mouse "
+                            + "can't pull the pointer away from where you're looking, and every mouse move is a real "
+                            + "correction, which the eye tracker learns from to get more accurate. If the eye "
+                            + "tracker stops (the headset is off, or it lost your eyes), the mouse moves the "
+                            + "pointer as usual."
+                          : "The mouse moves the pointer any time, as without gaze; looking well away hands the "
+                            + "pointer back to your eyes. Mouse moves that weren't corrections can teach the eye "
+                            + "tracker the wrong thing, so it may get less accurate."
+                    opacity: 0.7
+                    font: Kirigami.Theme.smallFont
+                }
                 Controls.Switch {
                     Kirigami.FormData.label: "Gaze dot:"
                     text: "Always shown (off: only while the mouse moves it)"