feat(data): schema v3 — an alarm or a timer that deletes itself after use

The `AlarmClock` contract says twice that an alarm or a timer created with
`SKIP_UI` should be removed once it has been dismissed. Without somewhere to
record that, a voice user's alarm list becomes a graveyard of one-shots nobody
asked to keep.

One column on each of `alarms` and `timers`, defaulting to 0, and a migration
that adds them. Existing rows keep the behaviour they have always had.

app/src/androidTest/java/de/jeanlucmakiola/clockula/data/db/MigrationTest.kt

@@ -35,6 +35,15 @@ class MigrationTest {
             1700000000000, 1700000060000)
     """.trimIndent()
 
+    private val insertTimer = """
+        INSERT INTO timers (
+            id, label, duration_millis, state, remaining_millis,
+            started_at_elapsed_realtime_millis, ends_at_elapsed_realtime_millis,
+            ends_at_wall_clock_millis, ringtone_uri, sort_order, created_at, updated_at
+        ) VALUES (1, 'Pasta', 300000, 'IDLE', 300000, NULL, NULL, NULL, NULL, 0,
+            1700000000000, 1700000060000)
+    """.trimIndent()
+
     private fun migratedDatabase(): ClockulaDatabase {
         val db = Room.databaseBuilder(
             ApplicationProvider.getApplicationContext(),
@@ -102,6 +111,33 @@ class MigrationTest {
         assertThat(runBlocking { db.alarmStateDao().findByAlarmId(1L) }).isNull()
     }
 
+    @Test
+    fun theSecondMigrationValidatesAgainstTheExportedVersionThreeSchema() {
+        helper.createDatabase(DB_NAME, 2).close()
+
+        val migrated = helper.runMigrationsAndValidate(DB_NAME, 3, true, Migrations.MIGRATION_2_3)
+
+        assertThat(migrated.version).isEqualTo(3)
+        migrated.close()
+    }
+
+    @Test
+    fun rowsWrittenAtVersionTwoSurviveAsPermanentOnes() {
+        helper.createDatabase(DB_NAME, 2).apply {
+            execSQL(insertAlarm)
+            execSQL(insertTimer)
+            close()
+        }
+
+        helper.runMigrationsAndValidate(DB_NAME, 3, true, Migrations.MIGRATION_2_3).close()
+
+        val db = migratedDatabase()
+        val alarm = runBlocking { db.alarmDao().findById(1L) }
+        val timer = runBlocking { db.timerDao().findById(1L) }
+        assertThat(alarm!!.deleteAfterUse).isFalse()
+        assertThat(timer!!.deleteAfterUse).isFalse()
+    }
+
     private fun ringStateFor(alarmId: Long) = AlarmStateEntity(
         alarmId = alarmId,
         snoozedUntil = 1_700_000_100_000L,