Development record

35-drain.md:252-253 says a pull request that turns conflicting after arming is refused by the run's own step 'since the drain's part ends at the open pull request', but the drain's move re-enters the sync for a parked lane whose conflict is confined to declared generated files or not reproducible here (internal/core/implement/loop/drain_finish.go:274-283), as commands/drain.md:407-412 and the chapter's own :413-416 say; :413-415 also omits the not-reproducible case commands/implement.md:471-472 names.