The http and slack targets sent the constant User-Agent webhooker/1.0. They now send webhooker/ followed by the version the build stamped, the same value the footer shows, built in one place on the delivery engine. User-Agent stays a reserved header and is still set after the target's configured headers, so a configured one cannot override it. Tests check the header each target sends against a known version, and that a configured User-Agent is replaced.
Model: opus-5-5
