Adds the SettingsPrefs surface the mirror is configured and reconciled through:
master enable, per-type toggles (default all three on), per-type managed calendar
id (source of truth for the editor's managedCalendarIds and the sync targets),
editable per-type title template, show-age, and a run/stalled status plus a
foreground-sync debounce timestamp.
Calendar ids are stored per type under their own long key (no serialization/
escaping); templates likewise per type. SpecialDatesStatus/StalledReason model
the paused (permission-revoked) state for the settings banner.
Extends the test FakeCalendarDataSource with a stateful managed-event surface
(inserts reflected in later queries) so the sync engine can be exercised for
idempotency. Round-trip tests for every new pref.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Jean-Luc Makiola
f7c0b8a957