More long-press accents; number-row letters stay choices in full mode

- Template alternates cover Central/Eastern European, Turkish, Romanian,
  Baltic, Nordic and Esperanto letters, at most 11 per key
- Only letters on the letter rows are skipped as choices, so sk ť, ľ, š…
  are offered on their base letter in full mode too

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

tests/tst_layoutbuilder.cpp

@@ -132,8 +132,9 @@ private Q_SLOTS:
         QCOMPARE(acute.deadShifted, quint32(XKB_KEY_dead_caron));
         QCOMPARE(letterKey(sk, u"ô"_s).shifted, u"\""); // as the physical key
         QCOMPARE(letterKey(sk, u"ľ"_s).shifted, u"2");
-        // ľ has its own key now, so it's not a long-press choice on l.
-        QVERIFY(!letterKey(sk, u"l"_s).alternates.contains(u"ľ"_s));
+        // Number-row letters are still long-press choices on their base letter.
+        QCOMPARE(letterKey(sk, u"t"_s).alternates.first(), u"ť");
+        QCOMPARE(letterKey(sk, u"l"_s).alternates.first(), u"ľ");
     }
 
     void noPlaceholdersRemain()