Events table missing columns for API fields

[dmwyatt]

Problem

The events table schema only stores a subset of the fields available from the Granola API. During sync, several fields from CalendarEvent are persisted, but others are silently dropped:

Stored: id, summary, start_time, end_time, calendar_id, attendees_json, conference_data_json, description, extra_json

Not stored: creator, organizer, recurring_event_id, ical_uid, status, html_link

When list_events() reconstructs CalendarEvent from the database, these fields are hardcoded to None (src/db/calendars.rs:87-93).

Investigation needed

• Are any of these fields useful for queries or display?
  • status (confirmed/tentative/cancelled) could be useful for filtering
  • html_link could be displayed in meeting detail views
  • recurring_event_id could help group recurring meetings
  • organizer/creator could enrich people-related queries
• Should these be added via a migration, or are they low-value enough to leave in extra_json?
• The extra_json column with #[serde(flatten)] may already capture some of these if the API sends them as part of the response — worth verifying

Context

Noticed during #231 (type consolidation) — the consolidated CalendarEvent type has all these fields, but the DB layer can't round-trip them.