Check Handle Available

Whether the company editor may offer handle. Advisory, never authoritative.

Byte-for-byte the same contract as GET /api/profile/handle-available, including the answers: a boolean and a coarse reason, never the holder. That is not duplication for its own sake -- the two editors are two screens asking one question about one namespace, and an answer that differed between them would be a bug in whichever one a user believed.

It checks both tables, and that is the whole reason it exists as a second endpoint rather than the profile one being reused. A company editor told that stripe is free because no other COMPANY holds it would let somebody publish a page that collides with a person, which is the collision the shared namespace exists to prevent.

Your own handle comes back available, whichever table holds it: reopening the editor and pressing Save without touching the field must not be told your own name is taken.

A shape violation is a false with reason: "invalid", not a 422. This is called as the user types, and "you have typed two characters so far" is not a client error.