Findings fixed:
1. TestAdversarial_ReconnectUsesHandshakeNotBootstrap now has 3 observable
proof points instead of just "SyncCache succeeded":
- new shipper HasFlushedProgress=true (seeded from old group)
- replica receivedLSN advances during SyncCache (catch-up delivered entries)
- shipper replicaFlushedLSN > 0 after barrier (durable progress established)
Bootstrap alone would not advance receivedLSN — it only sends the barrier.
2. TestBug2 stale comment removed: "must NOT call SetReplicaAddr" replaced
with accurate CP13-5 explanation that SetReplicaAddrs now preserves
hasFlushedProgress across shipper replacement.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
