Saves the camera's current position as a named preset. Move the camera to the desired position first.
The server picks the token, waits for the camera and registers the confirmed token in Cloud; the caller
cannot choose the token. Names are trimmed and must contain 1–100 characters.

The server tries "1", "2", "3" and up, skipping every token held by a Cloud preset or by a native preset
on the camera. There is no fixed limit of ten presets: on a camera that holds "1" to "10", the next preset
is created as "11". How many presets fit is up to the camera; a camera with no room left refuses the write
and the request fails. The camera may also store the position under a token of its own; the response
carries the token it confirmed.

When the camera's native presets include a token made only of digits other than "1" to "10" (for example
"0", "01" or "11"), the camera is treated as a fixed table of slots: creation overwrites the lowest native
preset that is not registered in Cloud, so register the native presets you want to keep.
PTZ_PRESET_SLOTS_EXHAUSTED (409) means every native preset is already registered.

Returns the ACTIVE Cloud record with HTTP 200. If the camera creates the preset but Cloud registration fails,
an unregistered native preset remains on the camera. Refresh GET presets and register it before editing the
camera. Do not retry preset creation.

HTTP 202 means the result is unconfirmed. Do not retry after a 202, timeout or connection loss until
you refresh the relevant data and reconcile the camera state.

Required scope: write:ptz