Merge release/v2.11.0 into feat/agenda-range-limit

Integrate #3/#5/#6 (week-start, time-format, hour-lines) into the agenda
range branch. SettingsViewModel folds all five view prefs into one combine;
WidgetData keeps the range-based window and adds the resolved is24Hour.

Also, in the same Appearance section:
- regroup the rows into four titled-by-spacing groups (theme & colour /
  calendar layout / timeline display / agenda) instead of one long card.
- add an explanatory description line under the title of each agenda-range
  picker (PickerDescription).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/src/main/res/values-de/strings.xml

@@ -276,10 +276,16 @@
     <string name="settings_dynamic_color_unavailable">Erfordert Android 12 oder neuer</string>
     <string name="settings_week_start">Wochenstart</string>
     <string name="settings_week_start_auto">Automatisch</string>
-    <string name="settings_week_start_monday">Montag</string>
-    <string name="settings_week_start_sunday">Sonntag</string>
+    <string name="settings_time_format">Zeitformat</string>
+    <string name="settings_time_format_auto">Automatisch</string>
+    <string name="settings_time_format_12h">12-Stunden (2:00 PM)</string>
+    <string name="settings_time_format_24h">24-Stunden (14:00)</string>
+    <string name="settings_hour_lines">Stundenlinien</string>
+    <string name="settings_hour_lines_summary">Trennlinie zu jeder vollen Stunde in Wochen- und Tagesansicht anzeigen</string>
     <string name="settings_agenda_range">Agenda-Zeitraum</string>
+    <string name="settings_agenda_range_hint">Wie weit im Voraus die Agenda-Ansicht Termine anzeigt.</string>
     <string name="settings_agenda_widget_range">Agenda-Widget-Zeitraum</string>
+    <string name="settings_agenda_widget_range_hint">Wie weit im Voraus das Agenda-Widget auf dem Startbildschirm Termine anzeigt.</string>
     <string name="agenda_range_day">Heute</string>
     <string name="agenda_range_this_week">Diese Woche</string>
     <string name="agenda_range_this_month">Dieser Monat</string>