Full keyboard: stagger the letter rows like a hardware keyboard

- The ISO key left of Z takes its room from left shift (2.25 → 1.25 + 1),
  so ISO layouts no longer make the shift row the widest
- Caps lock and left shift keep their width; only right-hand keys stretch,
  so A no longer lines up with the key below it

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

src/layout/LayoutBuilder.cpp

@@ -2,6 +2,8 @@
 
 #include <QSet>
 
+#include <algorithm>
+
 namespace {
 
 // Letters without a Unicode decomposition, and the key they belong under.
@@ -53,8 +55,10 @@ QList<KeyDef> letterKeys(const KeymapKeys &keymap, int row, const QStringList &f
 }
 
 // A full row: every typing key, the shifted symbol shown (and flickable) above.
-QList<KeyDef> rowKeys(const KeymapKeys &keymap, int row)
+// `withLessGreater` tells whether the ISO key left of Z is among them.
+QList<KeyDef> rowKeys(const KeymapKeys &keymap, int row, bool *withLessGreater)
 {
+    *withLessGreater = false;
     QSet<QString> elsewhere; // LSGT often repeats a pair that exists elsewhere (US: < >)
     for (const auto &keys : keymap.rows) {
         for (const KeymapKey &key : keys) {
@@ -67,6 +71,7 @@ QList<KeyDef> rowKeys(const KeymapKeys &keymap, int row)
     for (const KeymapKey &source : keymap.rows.value(row)) {
         if (source.position == KeymapKey::Position::LessGreater && elsewhere.contains(source.lower))
             continue;
+        *withLessGreater |= source.position == KeymapKey::Position::LessGreater;
         KeyDef key = characterKey(source);
         // Show (and flick for) a shifted level that isn't just the capital letter: ! on 1, " on sk ô.
         if (!source.deadUpper && source.upper != source.lower && source.upper != source.lower.toUpper())
@@ -82,8 +87,14 @@ Row expandPlaceholders(const Row &row, const KeymapKeys &keymap)
     for (const KeyDef &key : row) {
         if (key.type == KeyType::Letters)
             result += letterKeys(keymap, key.lettersRow, key.flicks);
-        else if (key.type == KeyType::Keys)
-            result += rowKeys(keymap, key.lettersRow);
+        else if (key.type == KeyType::Keys) {
+            bool withLessGreater = false;
+            const QList<KeyDef> keys = rowKeys(keymap, key.lettersRow, &withLessGreater);
+            // As on ISO keyboards, that key takes its room from the one before it (left shift).
+            if (withLessGreater && !result.isEmpty())
+                result.back().width = std::max(1.0, result.back().width - 1);
+            result += keys;
+        }
         else
             result.append(key);
     }