Add public/private calendars, full iCal support, and iCal URL import

- Public/private: toggle is_public via PUT /calendars/{id}; generate/clear
  public_token and return ical_url when public
- Public feed: GET /cal/{token}/feed.ics (no auth) for subscription in
  Google/Apple/Outlook calendars
- Full iCal export: use golang-ical; VALARM, ATTENDEE, all-day (VALUE=DATE),
  RRULE, DTSTAMP, CREATED, LAST-MODIFIED
- Full iCal import: parse TZID, VALUE=DATE, VALARM, ATTENDEE, RRULE
- Import from URL: POST /calendars/import-url with calendar_id + url
- Migration: unique index on public_token, calendar_subscriptions table
- Config: BASE_URL for ical_url; Calendar model + API: ical_url field
- Docs: OpenAPI, llms.txt, README, SKILL.md, about/overview

Made-with: Cursor

cmd/server/main.go

@@ -65,7 +65,7 @@ func main() {
 	auditSvc := service.NewAuditService(queries)
 	authSvc := service.NewAuthService(pool, queries, jwtManager, auditSvc)
 	userSvc := service.NewUserService(pool, queries, auditSvc)
-	calSvc := service.NewCalendarService(pool, queries, auditSvc)
+	calSvc := service.NewCalendarService(pool, queries, auditSvc, cfg.BaseURL)
 	eventSvc := service.NewEventService(pool, queries, calSvc, auditSvc, sched)
 	contactSvc := service.NewContactService(queries, auditSvc)
 	availSvc := service.NewAvailabilityService(queries, calSvc, eventSvc)