test(06-03): add failing tests for hasRrule + bounded expansion

- Add hasRrule===true assertion for recurring events (weekly-dst.ics)
- Add hasRrule===false assertion for non-recurring events (single-duration.ics)
- Add weekly-count3.ics fixture (FREQ=WEEKLY;COUNT=3, 1-hour events)
- Add bounded RRULE test: expects exactly 3 occurrences in wide window
- Add per-occurrence duration test: each occurrence is 1 hour (not recurrence span)
- Tests are RED: hasRrule field absent from CalendarOccurrence interface

apps/api/tests/fixtures/weekly-count3.ics

@@ -0,0 +1,12 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//FamilySync//Test//EN
+BEGIN:VEVENT
+UID:weekly-count3@familysync.test
+DTSTART:20260601T090000Z
+DTEND:20260601T100000Z
+RRULE:FREQ=WEEKLY;COUNT=3
+SUMMARY:Weekly Count 3
+DESCRIPTION:Bounded weekly series — exactly 3 occurrences (COUNT=3); each occurrence duration is 1 hour from DTSTART→DTEND
+END:VEVENT
+END:VCALENDAR