Includes two raft fixes the e2e exposed:
- heartbeatLoop drops cached peer sockets on leadership acquisition
(half-dead sockets to a restarted peer never errored, so no redial
ever happened and the cluster livelocked without heartbeats)
- restoreSnapshot repoints tcpServer ctx/db at the reopened database
(queries kept reading the closed pre-restore LSM, serving 0 rows)
