Backend: GET /api/settings/records/export downloads the clinic's full patient
archive as JSON; POST /api/settings/records/import creates new patients (skips
existing file numbers, drops cross-clinic provider links). Both admin-gated.
Frontend: Records settings now has a working Export button and an Import flow
(choose file -> preview count -> apply) wired to the new endpoints.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>