Fixed the 3 bug-411 baseline failures honestly: stale timeout
expectation updated to the reject-on-timeout contract (engine-wired
fixture, killing power retained); two healthy-primary gate fixtures
populated with standby_endpoints (gate logic untouched). Census: 46
groups / 467 tests / 0 failures standalone under default ASAN.
Audit (reviewer-confirmed, recorded in tasks.md): no production walAck
path reaches the deprecated acked_lsn>0 counting or n_active==0
short-circuit except the documented LSN-0 first entry. Leak inventory
for 6 groups documented as follow-up.
Rongsong Shen
95a10cedf3