Update Profile

Update the caller's researcher profile.

This used to write ONLY name while accepting the whole ProfileIn — so omicOS-ui's ProfileModal, which PATCHes the full form, silently lost institution / research_area / usage_purpose on every save. Worse, it then reported success and merged the form into its local copy, so the edit looked applied until the next login reloaded the untouched row from the server. The fields have been in the payload model since the profile form shipped; only the UPDATE was missing.

Semantics: a field is written only when the client SENDS it non-empty. ProfileIn defaults every field to "", and PATCH is a partial update, so a caller that omits a field (omicos-server-ui sends name only) must not have it blanked. Clearing a field is therefore not expressible here — no client offers it, and silently wiping data on a partial payload is the worse failure. title additionally goes through the closed vocabulary.