Floating polish: visibility, resize, saved geometry, D-Bus, desktop entry

- VisibilityController: show on field focus, dismiss until next focus,
  manual show/hide/toggle overrides
- FloatingWindow: resize from the corner grip, clamp to screen
- WindowSettings: geometry per screen, debounced saves
- DBusControl: org.sloposk.Keyboard Show/Hide/Toggle for global shortcuts
- org.sloposk.keyboard.desktop so System Settings lists it as a virtual keyboard
- README with build/run/layout docs

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

src/window/FloatingWindow.cpp

@@ -36,19 +36,44 @@ FloatingWindow::FloatingWindow(QWindow *window, QObject *parent)
     apply();
 }
 
-void FloatingWindow::setPosition(QPoint position)
+QRect FloatingWindow::geometry() const
 {
-    position = clamped(position);
-    if (position == m_position)
-        return;
-    m_position = position;
+    return {m_position, m_window->size()};
+}
+
+void FloatingWindow::setGeometry(const QRect &geometry)
+{
+    const QSize size = geometry.size().expandedTo(m_window->minimumSize()).boundedTo(screenArea().size());
+    m_window->resize(size);
+    m_position = clamped(geometry.topLeft(), size);
     apply();
-    Q_EMIT positionChanged();
+}
+
+QString FloatingWindow::screenName() const
+{
+    return m_window->screen()->name();
 }
 
 void FloatingWindow::moveBy(qreal dx, qreal dy)
 {
-    setPosition(m_position + QPoint(qRound(dx), qRound(dy)));
+    const QPoint position = clamped(m_position + QPoint(qRound(dx), qRound(dy)), m_window->size());
+    if (position == m_position)
+        return;
+    m_position = position;
+    apply();
+    Q_EMIT geometryChanged();
+}
+
+void FloatingWindow::resizeBy(qreal dw, qreal dh)
+{
+    const QSize maximum = screenArea().size() - QSize(m_position.x(), m_position.y());
+    const QSize size = (m_window->size() + QSize(qRound(dw), qRound(dh)))
+                           .expandedTo(m_window->minimumSize())
+                           .boundedTo(maximum);
+    if (size == m_window->size())
+        return;
+    m_window->resize(size);
+    Q_EMIT geometryChanged();
 }
 
 void FloatingWindow::setInputRegion(const QRectF &region)
@@ -66,19 +91,24 @@ void FloatingWindow::hide()
     m_window->setVisible(false);
 }
 
-QPoint FloatingWindow::clamped(QPoint position) const
+QRect FloatingWindow::screenArea() const
 {
-    const QRect area = m_window->screen()->geometry();
-    const int maxX = qMax(0, area.width() - m_window->width());
-    const int maxY = qMax(0, area.height() - m_window->height());
+    return m_window->screen()->geometry();
+}
+
+QPoint FloatingWindow::clamped(QPoint position, QSize size) const
+{
+    const QRect area = screenArea();
+    const int maxX = qMax(0, area.width() - size.width());
+    const int maxY = qMax(0, area.height() - size.height());
     return {qBound(0, position.x(), maxX), qBound(0, position.y(), maxY)};
 }
 
 QPoint FloatingWindow::defaultPosition() const
 {
-    const QRect area = m_window->screen()->geometry();
-    return clamped({(area.width() - m_window->width()) / 2,
-                    area.height() - m_window->height() - BottomGap});
+    const QRect area = screenArea();
+    return clamped({(area.width() - m_window->width()) / 2, area.height() - m_window->height() - BottomGap},
+                   m_window->size());
 }
 
 void FloatingWindow::apply()
@@ -86,5 +116,5 @@ void FloatingWindow::apply()
     if (m_layerSurface)
         m_layerSurface->setMargins({m_position.x(), m_position.y(), 0, 0});
     else
-        m_window->setPosition(m_window->screen()->geometry().topLeft() + m_position);
+        m_window->setPosition(screenArea().topLeft() + m_position);
 }