fix(clinician-share): a document share exposes only the document

Sharing a single document from the vault minted a full-record share: the
create form always defaulted `resourceTypes` to ["Patient","Observation"]
and never signalled a documents-only intent, so the served /c/<token> view
aggregated the whole doctor report — every vital, lab, medication and
wellness figure — alongside the attached file. An empty section blob was
indistinguishable from "defaults", so the report always resolved to the
full record.

Introduce an explicit documents-only share:

- add a `documentOnly` flag to the create payload; when set the server
  forces an empty report scope (all-off sections, no FHIR resource types,
  FHIR API off) and requires at least one document, so a document link can
  never widen into a record — whatever the body sends.
- gate the clinician-view aggregation on an enabled section: a share with
  no section on never calls the report aggregator, so no health metric
  leaves the database. The recipient sees only the attached document(s).
- the document detail Share action opens the create form in documents-only
  mode: hide the FHIR toggle, the FHIR resource-type checkboxes and the
  history-range selector, keep the picker/label/expiry/passphrase, and
  always carry the launched document into the created link.
- Settings sharing keeps the full record-share form unchanged.

Extract the create-payload builder as a pure function and cover the scope
contract, the empty-scope data load, and the served-view metric-free
guarantee with tests; refresh the share e2e and regenerate the OpenAPI
contract.

src/components/documents/document-share-sheet.tsx

@@ -40,6 +40,7 @@ export function DocumentShareSheet({
     >
       {open ? (
         <ShareLinkCreateForm
+          documentOnly
           initialDocuments={[{ id: documentId, title: documentTitle }]}
           initialLabel={documentTitle}
         />