feat(alarms): schedule an alarm on a date, pause a repeating one

A one-shot alarm can now ring on a chosen date, and a repeating alarm
can be paused for a range of days. Both are local dates: the date is a
floor and the pause a hole in the occurrence sequence, so DST and zone
changes resolve as for any other alarm. A missed date behaves like a
missed one-shot, and each clears itself once it can no longer change a
candidate. Picking a repeat day clears the date, as in Google Clock;
"skip next" stays the quick version of a pause.

The editor uses the M3 date and date-range pickers, which offer no past
day. The list, the next-alarm widget and the self-check read the
resolver, so they follow. The schema goes to v4 with a migration, and
the backup format to v2, which still imports v1 files. SET_ALARM no
longer re-uses an alarm that carries a date or a pause.

Fixes #21

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

@@ -118,6 +118,12 @@
     <string name="alarm_repeat_every_day">Every day</string>
     <string name="alarm_repeat_weekdays">Weekdays</string>
     <string name="alarm_repeat_weekends">Weekends</string>
+    <!-- %1$s is a date such as "Wed, Oct 28" -->
+    <string name="alarm_scheduled_for">Scheduled for %1$s</string>
+    <!-- %1$s is a date range such as "Oct 26 – 28" -->
+    <string name="alarm_paused_dates">Paused %1$s</string>
+    <!-- %1$s is a date such as "Oct 28": the pause has already begun -->
+    <string name="alarm_paused_until">Paused until %1$s</string>
     <string name="alarm_summary_separator" translatable="false">" \u00b7 "</string>
 
     <!-- M5: the alarm editor -->
@@ -125,6 +131,10 @@
     <string name="editor_repeat">Repeat</string>
     <string name="editor_skip_next">Skip next alarm</string>
     <string name="editor_skip_next_summary">Ring the one after this</string>
+    <string name="editor_schedule">Schedule alarm</string>
+    <string name="editor_schedule_none">Pick a date for this alarm to ring on</string>
+    <string name="editor_pause">Pause alarm</string>
+    <string name="editor_pause_none">Keep it quiet for a few days, such as a holiday</string>
     <string name="editor_label_placeholder">Alarm name</string>
     <string name="editor_section_sound">Sound and vibration</string>
     <string name="editor_section_snooze">Snooze and dismiss</string>