Fix recover path TOCTOU: re-Lookup after AddReplica so the primary
refresh assignment includes the freshly added replica addresses.
Previously, Lookup (copy) was called before AddReplica modified the
registry, so entry.Replicas was empty → primary got replicas=0 →
shipper never configured.
Add 2 WAL pressure edge case tests:
- ShipperCatchUpOrEscalate: 64KB WAL, 200 writes, aggressive flusher.
Proves no hang/deadlock/corruption. Shipper either keeps up or
correctly escalates to NeedsRebuild.
- RebuildWithPinWhilePrimaryWrites: rebuild session active while
primary writes 7600+ blocks in 2s. Proves primary never freezes
— rebuild pin is on replica only, primary WAL recycles freely.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
pingqiuandClaude Opus 4.6
53246d2780