- Move repl.h from controller/ to include/ (shared header) to break
persist.h ↔ repl.h circular include
- Extract wal_entry_hdr_t + wal_entry_type into include/wal_types.h so
repl.h can include only what it needs without pulling in all of persist.h
- Add replicator_t repl field to persist_t (embedded by value, P2-4)
- Wire repl_init/repl_fini into persist_init/persist_fini lifecycle
- Wire repl_broadcast into persist_wal_async after each WAL write;
last_replicated_crc updated here (not in persist_write_checkpoint_marker)
- Wire repl_wait_ack into persist_wal_sync_append; returns 0 on local
WAL success; sync_rc_out carries -ENODEV/-ETIMEDOUT for degraded mode
- Add 4 TDD tests in test_persist_repl.c: structural repl field check,
async no-standbys succeeds, sync degraded mode rc, checkpoint CRC invariant
Add replicator_t structure with per-standby connection slots (standby_conn_t),
lifecycle (repl_init/repl_fini), slot management (repl_add_standby,
repl_remove_standby, repl_expire_disconnect_slots), ACK tracking
(repl_on_ack), WAL trim guard (repl_trim_lsn), and stubs for
repl_broadcast/repl_wait_ack (wired in P2-3/P2-4).
Uses mylock_t (pthread_mutex_t alias) with mylock_lock/mylock_unlock.
snap_interval_s==0 in repl_expire_disconnect_slots forces immediate expiry
to support deterministic unit testing.
5 new Unity tests all pass; 115 pre-existing controller tests unchanged.
