Split the two prefill paths that share openImported(): an ACTION_INSERT
intent still auto-applies the settings default (it carries no reminder
semantics), but a .ics file — which owns its reminders — no longer silently
decides. It keeps the file's reminders and raises a one-time prompt
("This event was imported with N reminder(s) — apply your default?") so the
user chooses. The prompt is skipped when there's no real choice: no default
configured, or the file already carries exactly it.
openImported() now takes an ImportSource; CalendarHost tags the overlay
Insert vs File. Accepting swaps in the default and reveals the section;
declining (or dismissing) keeps the file's own reminders.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>