fix(edit): use the family's text input, and show both times when zones differ

Two review fixes.

The zone picker's search box was a raw Material OutlinedTextField — the
only one left in the app, and against the convention DialogControls
states outright ("the family's InlineTextField over a tonal surface, not
Material's outlined field"). Rebuild it on InlineTextField over a tonal
surface, with the clear button inside the surface since the picker's top
bar is the title rather than a search field.

Showing a pinned event only in its own zone answered "what was it set
to?" while dropping "when is it for me?" — the user had to do the offset
arithmetic. Show both whenever they differ:

- the edit form keeps editing the event in its own zone (that's the time
  it was set at) and captions it with the local equivalent;
- the detail screen keeps local times primary and now leads the zone card
  with the original ("8:00 AM – 9:00 AM in New York") instead of naming
  the zone and nothing else.

EventForm.timesIn is pure, so the conversion — including crossing the
date line and each zone's own DST, which don't move together — is a
plain JUnit test rather than something only reviewable on a phone.

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

app/src/test/java/de/jeanlucmakiola/calendula/domain/EventFormTest.kt

@@ -209,6 +209,67 @@ class EventFormTest {
         assertThat(prefilled.start).isEqualTo(LocalDateTime(LocalDate(2026, 6, 11), LocalTime(10, 0)))
     }
 
+    @Test
+    fun `timesIn converts a pinned event into the target zone`() {
+        val form = EventForm(
+            calendarId = 1L,
+            start = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(8, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(9, 0)),
+            timezone = "America/New_York",
+        )
+        val (start, end) = form.timesIn(berlin)!!
+        // 08:00 New York (EDT, UTC-4) is 14:00 Berlin (CEST, UTC+2).
+        assertThat(start).isEqualTo(LocalDateTime(LocalDate(2026, 7, 17), LocalTime(14, 0)))
+        assertThat(end).isEqualTo(LocalDateTime(LocalDate(2026, 7, 17), LocalTime(15, 0)))
+    }
+
+    @Test
+    fun `timesIn crosses the date line when the offset pushes past midnight`() {
+        val form = EventForm(
+            calendarId = 1L,
+            start = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(20, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(21, 0)),
+            timezone = "America/New_York",
+        )
+        val (start, _) = form.timesIn(berlin)!!
+        // 20:00 New York is 02:00 the NEXT day in Berlin — the date has to move
+        // with it, not just the clock.
+        assertThat(start).isEqualTo(LocalDateTime(LocalDate(2026, 7, 18), LocalTime(2, 0)))
+    }
+
+    @Test
+    fun `timesIn tracks each zone's own DST rather than a fixed offset`() {
+        // In January both are on standard time: 08:00 EST is 14:00 CET — the
+        // same six hours as July, but only because both shifted. Late March,
+        // when the US has sprung forward and Europe hasn't, the gap is five.
+        val march = EventForm(
+            calendarId = 1L,
+            start = LocalDateTime(LocalDate(2026, 3, 20), LocalTime(8, 0)),
+            end = LocalDateTime(LocalDate(2026, 3, 20), LocalTime(9, 0)),
+            timezone = "America/New_York",
+        )
+        assertThat(march.timesIn(berlin)!!.first)
+            .isEqualTo(LocalDateTime(LocalDate(2026, 3, 20), LocalTime(13, 0)))
+    }
+
+    @Test
+    fun `timesIn returns null when there is nothing to disambiguate`() {
+        val base = EventForm(
+            calendarId = 1L,
+            start = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(8, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(9, 0)),
+        )
+        // Unpinned: the form's times already are the local times.
+        assertThat(base.timesIn(berlin)).isNull()
+        // Pinned to the target itself: same thing.
+        assertThat(base.copy(timezone = "Europe/Berlin").timesIn(berlin)).isNull()
+        // All-day: date-anchored, so there's no zone conversion to show.
+        assertThat(base.copy(isAllDay = true, timezone = "America/New_York").timesIn(berlin))
+            .isNull()
+        // Unparseable: can't convert, mustn't throw.
+        assertThat(base.copy(timezone = "Mars/Olympus_Mons").timesIn(berlin)).isNull()
+    }
+
     @Test
     fun `toEditForm turns the exclusive all-day end into the last covered day`() {
         // 11th..13th = UTC midnights of the 11th and the (exclusive) 14th.