Full keyboard mode, Ctrl/Alt/Super, dead keys, shift levels

- Full (iPad Pro) mode: every typing key from the keymap, number row,
  tab, caps lock, ctrl/super/alt; shifted symbol shown above and flickable
- Dead keys compose with the locale's XKB compose table
- Ctrl/Alt/Super stick like shift and turn keys into shortcuts; a tapped
  or held shift joins shortcuts and non-text keys, auto-shift and caps
  lock don't
- Auto-capitalization and caps lock only capitalize letters; the user's
  shift picks the keymap's shifted level
- Mode switch in settings keeps key size by resizing the window

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

tests/tst_layoutloader.cpp

@@ -72,14 +72,18 @@ private Q_SLOTS:
     void builtLayersHaveEvenRows_data()
     {
         QTest::addColumn<QString>("xkbLayout");
-        for (const char *layout : {"us", "sk", "se", "de", "fr", "ru", "gr"})
-            QTest::newRow(layout) << QString::fromLatin1(layout);
+        QTest::addColumn<KeyboardMode>("mode");
+        for (const char *layout : {"us", "sk", "se", "de", "fr", "ru", "gr"}) {
+            QTest::addRow("%s compact", layout) << QString::fromLatin1(layout) << KeyboardMode::Compact;
+            QTest::addRow("%s full", layout) << QString::fromLatin1(layout) << KeyboardMode::Full;
+        }
     }
 
     void builtLayersHaveEvenRows()
     {
         QFETCH(QString, xkbLayout);
-        const Layout layout = TestLayouts::build(qPrintable(xkbLayout));
+        QFETCH(KeyboardMode, mode);
+        const Layout layout = TestLayouts::build(qPrintable(xkbLayout), mode);
         for (const Layer &layer : layout.layers) {
             const QList<QRectF> rects = computeKeyRects(layer, {1000, 300});
             qsizetype i = 0;