WORKER.md: keep a heartbeat on stdout in build-server jobs
Merged
AF
30m ago+9+9+0123456789-0-0-0123456789
Workers write long job output to a file, which made two jobs today look hung after 15+ minutes of silence. Nobody can see inside a running build-server job, so this asks for a progress line at least once a minute and a time limit per long step that names the step it stopped in. Docs only.
Summary by cubic
Adds a documentation rule requiring build-server jobs to print a heartbeat on stdout at least once a minute. Two jobs today looked hung after 15+ minutes of silence because their output went only to a job-local file, so the new guidance asks for progress lines and per-step time limits that name the step they stopped in. Docs only.