Mints a fresh upload destination for a session recording: storage
credentials plus the server-built bucket/key. The server owns the storage
layout and the identity in the path (ctx.user), so clients never decode
tokens or construct keys. A mutation (not a query): each call returns a new
timestamped key, and caching a stale one would silently overwrite a prior
recording on retry.
Mints a fresh upload destination for a session recording: storage credentials plus the server-built bucket/key. The server owns the storage layout and the identity in the path (
ctx.user), so clients never decode tokens or construct keys. A mutation (not a query): each call returns a new timestamped key, and caching a stale one would silently overwrite a prior recording on retry.