Measured on dev: with the user's cookie some reels still answer "Cannot parse
data" and only extract when the request impersonates Chrome. Impersonation is
a second attempt behind that one error, only when a cookie is attached — links
that already download with the cookie keep their plain path, and without a
cookie the same error is the login wall.
curl_cffi is pinned inside yt-dlp's supported range (0.10-0.15; outside it
every target silently reports "unavailable"); the lock only gains the new
packages. A test fails the gate if the locked pair can no longer impersonate.