Add “Care Team” sharing & permissions

Description:
Enable users to securely share their SymptomSync data (medication schedules, appointments, health logs) with trusted caregivers or family members (“Care Team”). Invitees should have configurable view-only or edit permissions and see real-time updates. This will help patients collaborate with doctors, nurses, or loved ones to better manage their health.

Acceptance Criteria:

1. Invite Flow:
   • User can open a “Care Team” panel from Settings and send email invites to one or more caregivers.
   • Invites include a secure, time-limited signup link.
2. Permissions Model:
   • Two permission levels: View-only (read data) and Editor (add/edit logs, reminders, appointments).
   • Owner can upgrade/downgrade or revoke access at any time.
3. UI & Dashboard:
   • Care Team members see a filtered dashboard showing only the patient’s data they have access to.
   • Patient sees a list of current Care Team members with their permission level.
4. Real-Time Sync:
   • Any changes by patient or Editor-level caregivers sync in real time across all devices (via Supabase Realtime).
5. Security & Privacy:
   • All shared data respects existing RLS policies—caregivers cannot access unrelated users’ data.
   • Audit log in database (timestamp, actor, action) for all create/update/delete by Care Team.
6. Notifications:
   • Email alert to caregivers when invited, permission changed, or revoked.
   • In-app notification for patient when a caregiver makes edits.

Tasks:

• Define new care_team table in Supabase with columns id, patient_id, user_id, permission_level, status, created_at.
• Create invitation API endpoints:
  • POST /api/care-team/invite
  • GET /api/care-team/pending
  • POST /api/care-team/accept/:token
  • PATCH /api/care-team/:id (update/revoke)
• Build frontend Care Team management UI under Settings: invite form, member list with permission controls.
• Generate secure JWT-based invite tokens (expires in 7 days).
• Implement RLS policies for care_team and resource tables to enforce view/edit permissions.
• Wire up Supabase Realtime subscriptions so both patient and editors see live updates.
• Send transactional emails via existing Supabase Functions when invites sent/accepted/revoked.
• Add audit-log triggers in Postgres for all care_team-related actions.
• Write Jest & Playwright tests covering invite flow, permission enforcement, and real-time sync.
• Update Swagger docs with new care-team endpoints and examples.

Estimated Effort: ~3–4 sprints