fix(edit): apply default reminder to ACTION_INSERT events (#49)

External ACTION_INSERT launches (e.g. Google Maps' "add to calendar",
the Todo Agenda widget) share the single-event .ics prefill channel:
CalendarHost routes requestedInsertForm as importForm, so EventEditScreen
calls openImported(), which froze reminders as touched to respect a file's
own VALARMs. But an insert intent carries no reminders, so the empty freeze
just suppressed the configured settings default — the event opened (and
saved) with no reminder.

Make the freeze follow the source, not the path: a form that carries its
own reminders (an .ics with VALARMs) still freezes them; a form with none
(every insert intent, and an .ics without VALARMs) falls back to the
settings default via applyDefaultReminder(), exactly like openNew(). An
intent that did carry reminders still wins.

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

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditViewModel.kt

@@ -241,18 +241,31 @@ class EventEditViewModel @Inject constructor(
     }
 
     /**
-     * Seed a fresh event from a parsed `.ics` file (the single-event "open into
+     * Seed a fresh event from a prefilled [form] — a parsed single-event `.ics`
-     * the create form" path). [form] already carries the file's fields; its
+     * file or an external `ACTION_INSERT` intent (another app/widget creating an
-     * [EventForm.calendarId] is null so the calendar still resolves to the
+     * event, e.g. Google Maps' "add to calendar"; #30, #49). [EventForm.calendarId]
-     * last-used/first-writable one, and reminders are frozen as touched so the
+     * is null so the calendar still resolves to the last-used/first-writable one.
-     * settings default never overwrites what the file specified. No-op when a
+     *
-     * form is already open, so the prefill survives configuration changes.
+     * Reminders follow the source rather than the path: a form that carries its
+     * own (an `.ics` with VALARMs) freezes them as touched, so the settings
+     * default never overwrites what it specified; a form with none — every
+     * insert intent, and an `.ics` without VALARMs — falls back to the settings
+     * default exactly like [openNew], instead of the empty freeze suppressing it.
+     * No-op when a form is already open, so the prefill survives configuration
+     * changes.
      */
     fun openImported(form: EventForm) {
         if (_form.value != null || _editTarget.value != null) return
-        _remindersTouched.value = true
         _revealed.value = form.populatedFields()
         _form.value = form
+        if (form.reminders.isNotEmpty()) {
+            // Source specified its own reminders — freeze so the default can't
+            // clobber them (and a later calendar/all-day switch won't re-apply).
+            _remindersTouched.value = true
+        } else {
+            // Nothing carried: inherit the settings default like a new event.
+            applyDefaultReminder()
+        }
     }
 
     /**