Development record

The embargo chapter says the check reads, over a commit range, messages and added lines (.abcd/development/brief/04-surfaces/37-embargo.md:86-87), and `abcd embargo check --help` says the same. The check also scans the names of files a commit adds, reporting 'a file name the commit adds' (internal/core/embargo/check.go:316). commands/embargo.md:175 states this; the chapter and the help do not.