Mirror the sibling last_known_committed_lsn: all writes release, reads acquire.
Prereq for a heartbeat-receive writer + the ctrlstatus reader to interact
safely (Req 2.3). Pure access migration, no behavior change; controller suite
0 failures.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Role-branch the committed sourcing: PRIMARY reports its own authoritative
persist.committed_lsn / committed_config_tag; off-primary reports the LEARNED
ha->last_known_committed_lsn / last_known_committed_config_tag instead of the
primary-only raw markers that read 0 on a standby (fixes the applied>committed
inversion). Stamp responder_time_ms from CLOCK_REALTIME for log correlation.
Read-only (Req 10.1-10.4, 11.1). 4 new TDD tests; controller suite 110/0/0.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
