feat(ui): login disclaimer line for the guest offline mode

One sentence under the subscription notice so the always-visible
'Start offline' link is self-explanatory: QBZ works as an offline
player without a Qobuz account, with no access to the Qobuz library.
One msgid x7 locales.

cc

crates/qbz-ui/translations/de/LC_MESSAGES/qbz-ui.po

@@ -4451,3 +4451,7 @@ msgstr "SONSTIGES"
 
 msgid "Border"
 msgstr "Rand"
+
+# Guest local-only mode disclaimer line (login screen, #553)
+msgid "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."
+msgstr "QBZ kann ohne Qobuz™-Konto als Offline-Player genutzt werden (kein Zugriff auf die Qobuz™-Bibliothek)."

crates/qbz-ui/translations/en/LC_MESSAGES/qbz-ui.po

@@ -223,3 +223,7 @@ msgstr "Border"
 
 msgid "Favorite"
 msgstr "Favorite"
+
+# Guest local-only mode disclaimer line (login screen, #553)
+msgid "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."
+msgstr "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."

crates/qbz-ui/translations/es/LC_MESSAGES/qbz-ui.po

@@ -4481,3 +4481,7 @@ msgstr "OTROS"
 
 msgid "Border"
 msgstr "Borde"
+
+# Guest local-only mode disclaimer line (login screen, #553)
+msgid "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."
+msgstr "QBZ puede usarse como reproductor sin conexión sin una cuenta de Qobuz™ (sin acceso a la biblioteca de Qobuz™)."

crates/qbz-ui/translations/fr/LC_MESSAGES/qbz-ui.po

@@ -4451,3 +4451,7 @@ msgstr "AUTRE"
 
 msgid "Border"
 msgstr "Bordure"
+
+# Guest local-only mode disclaimer line (login screen, #553)
+msgid "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."
+msgstr "QBZ peut être utilisé comme lecteur hors ligne sans compte Qobuz™ (pas d'accès à la bibliothèque Qobuz™)."

crates/qbz-ui/translations/ja/LC_MESSAGES/qbz-ui.po

@@ -4440,3 +4440,7 @@ msgstr "その他"
 
 msgid "Border"
 msgstr "境界線"
+
+# Guest local-only mode disclaimer line (login screen, #553)
+msgid "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."
+msgstr "QBZはQobuz™アカウントなしでオフラインプレーヤーとして使用できます（Qobuz™ライブラリにはアクセスできません）。"

crates/qbz-ui/translations/pt/LC_MESSAGES/qbz-ui.po

@@ -4451,3 +4451,7 @@ msgstr "OUTROS"
 
 msgid "Border"
 msgstr "Borda"
+
+# Guest local-only mode disclaimer line (login screen, #553)
+msgid "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."
+msgstr "O QBZ pode ser usado como reprodutor offline sem conta Qobuz™ (sem acesso à biblioteca Qobuz™)."

crates/qbz-ui/translations/ru/LC_MESSAGES/qbz-ui.po

@@ -4464,3 +4464,7 @@ msgstr "ДРУГОЕ"
 
 msgid "Border"
 msgstr "Граница"
+
+# Guest local-only mode disclaimer line (login screen, #553)
+msgid "QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library)."
+msgstr "QBZ можно использовать как офлайн-плеер без учётной записи Qobuz™ (без доступа к библиотеке Qobuz™)."

crates/qbz-ui/ui/login/LoginScreen.slint

@@ -276,6 +276,8 @@ export component LoginScreen inherits Rectangle {
                     // --- Legal disclaimer ------------------------------------
                     Text {
                         text: @tr("QBZ requires an active Qobuz™ subscription. Your credentials are sent directly to Qobuz™.")
+                            + "\n"
+                            + @tr("QBZ can be used as an offline player without a Qobuz™ account (no access to the Qobuz™ library).")
                             + "\n"
                             + @tr("This application uses the Qobuz API but is not certified by Qobuz.")
                             + " "